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Random lasers (RLs), which possess peculiar advantages (e.g., emission and coherence tunable) over traditional lasers with optical resonators, have witnessed rapid development in the past decades. However, it is still a challenge to tune the lasing peak of an RL over a wide range. Here, a temperature-dependent Förster resonance energy transfer (FRET) RL is demonstrated in pyrromethene 597 (PM597, “donor”) and Nile blue (NB, “acceptor”) doped chiral liquid crystals. By changing the temperature that drives the liquid crystal bandgap shift, our RL device exhibits a lasing output change from 560 nm (yellow) to 700 nm (red). While the intrinsic FRET efficiency between PM597 and NB is relatively low, the red lasing is weak. By introducing gold nanorods (GNRs) into these RL devices and utilizing GNRs’ localized surface plasmon resonance (LSPR) effect, the efficiency of FRET transfer is increased by 68.9%, thereby reducing the threshold of the RL devices. By tuning the longitudinal LSPR to match the emission wavelength of NB, the best 200-fold lasing intensity enhancement is recorded. Our findings open a pathway toward realizing LSPR-enhanced FRET tunable RLs and broaden the range of their possible exploration in photonics research and technologies.

Replica symmetry breaking (RSB) has been widely recognized as a statistical analysis approach to understand the disorder and nonlinear interactions in complex systems ranging from atoms to the cosmic scale. However, it is challenging to analyze the nonlinear optical characteristics of random laser (RL) in disordered gain medium via RSB due to the lack of a general RSB-based statistical analysis framework. In this work, we report the tunable RSB in polymer fiber RL, where the effects of temperature and different structures on RSB are investigated experimentally and theoretically. It experimentally proves that RSB in RL is not robust, and disorder and temperature are responsible for tunable RSB in RL, which contributes to the improvement of the statistical analysis framework for investigating the optical principles of RL using RSB. And the finding of the tunable RSB allows to investigate the dynamical differences for various RL systems, which broadens the directions for the use of spin-glass theory to explore the physical mechanism of RL.

Random lasers (RLs), which possess peculiar advantages (e.g., emission and coherence tunable) over traditional lasers with optical resonators, have witnessed rapid development in the past decades. However, it is still a challenge to tune the lasing peak of an RL over a wide range. Here, a temperature-dependent Förster resonance energy transfer (FRET) RL is demonstrated in pyrromethene 597 (PM597, “donor”) and Nile blue (NB, “acceptor”) doped chiral liquid crystals. By changing the temperature that drives the liquid crystal bandgap shift, our RL device exhibits a lasing output change from 560 nm (yellow) to 700 nm (red). While the intrinsic FRET efficiency between PM597 and NB is relatively low, the red lasing is weak. By introducing gold nanorods (GNRs) into these RL devices and utilizing GNRs’ localized surface plasmon resonance (LSPR) effect, the efficiency of FRET transfer is increased by 68.9%, thereby reducing the threshold of the RL devices. By tuning the longitudinal LSPR to match the emission wavelength of NB, the best 200-fold lasing intensity enhancement is recorded. Our findings open a pathway toward realizing LSPR-enhanced FRET tunable RLs and broaden the range of their possible exploration in photonics research and technologies.

Replica symmetry breaking (RSB) has been widely recognized as a statistical analysis approach to understand the disorder and nonlinear interactions in complex systems ranging from atoms to the cosmic scale. However, it is challenging to analyze the nonlinear optical characteristics of random laser (RL) in disordered gain medium via RSB due to the lack of a general RSB-based statistical analysis framework. In this work, we report the tunable RSB in polymer fiber RL, where the effects of temperature and different structures on RSB are investigated experimentally and theoretically. It experimentally proves that RSB in RL is not robust, and disorder and temperature are responsible for tunable RSB in RL, which contributes to the improvement of the statistical analysis framework for investigating the optical principles of RL using RSB. And the finding of the tunable RSB allows to investigate the dynamical differences for various RL systems, which broadens the directions for the use of spin-glass theory to explore the physical mechanism of RL.

We have demonstrated the realization of a coherent vesicle random lasing (VRL) from the dye doped azobenzene polymer vesicles self-assembled in the tetrahydrofuran-water system, which contains a double-walled structure: a hydrophilic and hydrophobic part. The effect of the dye and azobenzene polymer concentration on the threshold of random laser has been researched. The threshold of random laser decreases with an increase in the concentration of the pyrromethene 597 (PM597) laser and azobenzene polymer. Moreover, the scattering of small size group vesicles is attributed to providing a loop to boost the coherent random laser through the Fourier transform analysis. Due to the vesicles having the similar structure with the cell, the generation of coherent random lasers from vesicles expand random lasers to the biomedicine filed.

In this paper, pure silk protein was extracted from Bombyx mori silks and fabricated into a new kind of disordered bio-microfiber structure using electrospinning technology. Coherent random lasing emission with low threshold was achieved in the silk fibroin fibers. The random lasing emission wavelength can be tuned in the range of 33 nm by controlling the pump location with different scattering strengths. Therefore, the bio-microfiber random lasers can be a wide spectral light source when the system is doped with a gain or energy transfer medium with a large fluorescence emission band. Application of the random lasers of the bio-microfibers as a low-coherence light source in speckle-free imaging had also been studied.

We have demonstrated the realization of a coherent vesicle random lasing (VRL) from the dye doped azobenzene polymer vesicles self-assembled in the tetrahydrofuran-water system, which contains a double-walled structure: a hydrophilic and hydrophobic part. The effect of the dye and azobenzene polymer concentration on the threshold of random laser has been researched. The threshold of random laser decreases with an increase in the concentration of the pyrromethene 597 (PM597) laser and azobenzene polymer. Moreover, the scattering of small size group vesicles is attributed to providing a loop to boost the coherent random laser through the Fourier transform analysis. Due to the vesicles having the similar structure with the cell, the generation of coherent random lasers from vesicles expand random lasers to the biomedicine filed.

In this paper, pure silk protein was extracted from Bombyx mori silks and fabricated into a new kind of disordered bio-microfiber structure using electrospinning technology. Coherent random lasing emission with low threshold was achieved in the silk fibroin fibers. The random lasing emission wavelength can be tuned in the range of 33 nm by controlling the pump location with different scattering strengths. Therefore, the bio-microfiber random lasers can be a wide spectral light source when the system is doped with a gain or energy transfer medium with a large fluorescence emission band. Application of the random lasers of the bio-microfibers as a low-coherence light source in speckle-free imaging had also been studied.

We have demonstrated the realization of a coherent vesicle random lasing (VRL) from the dye doped azobenzene polymer vesicles self-assembled in the tetrahydrofuran-water system, which contains a double-walled structure: a hydrophilic and hydrophobic part. The effect of the dye and azobenzene polymer concentration on the threshold of random laser has been researched. The threshold of random laser decreases with an increase in the concentration of the pyrromethene 597 (PM597) laser and azobenzene polymer. Moreover, the scattering of small size group vesicles is attributed to providing a loop to boost the coherent random laser through the Fourier transform analysis. Due to the vesicles having the similar structure with the cell, the generation of coherent random lasers from vesicles expand random lasers to the biomedicine filed.

In this paper, pure silk protein was extracted from Bombyx mori silks and fabricated into a new kind of disordered bio-microfiber structure using electrospinning technology. Coherent random lasing emission with low threshold was achieved in the silk fibroin fibers. The random lasing emission wavelength can be tuned in the range of 33 nm by controlling the pump location with different scattering strengths. Therefore, the bio-microfiber random lasers can be a wide spectral light source when the system is doped with a gain or energy transfer medium with a large fluorescence emission band. Application of the random lasers of the bio-microfibers as a low-coherence light source in speckle-free imaging had also been studied.

We have demonstrated the realization of a coherent vesicle random lasing (VRL) from the dye doped azobenzene polymer vesicles self-assembled in the tetrahydrofuran-water system, which contains a double-walled structure: a hydrophilic and hydrophobic part. The effect of the dye and azobenzene polymer concentration on the threshold of random laser has been researched. The threshold of random laser decreases with an increase in the concentration of the pyrromethene 597 (PM597) laser and azobenzene polymer. Moreover, the scattering of small size group vesicles is attributed to providing a loop to boost the coherent random laser through the Fourier transform analysis. Due to the vesicles having the similar structure with the cell, the generation of coherent random lasers from vesicles expand random lasers to the biomedicine filed.

In this paper, pure silk protein was extracted from Bombyx mori silks and fabricated into a new kind of disordered bio-microfiber structure using electrospinning technology. Coherent random lasing emission with low threshold was achieved in the silk fibroin fibers. The random lasing emission wavelength can be tuned in the range of 33 nm by controlling the pump location with different scattering strengths. Therefore, the bio-microfiber random lasers can be a wide spectral light source when the system is doped with a gain or energy transfer medium with a large fluorescence emission band. Application of the random lasers of the bio-microfibers as a low-coherence light source in speckle-free imaging had also been studied.

Plasmonic nanorod metamaterials exhibit transversal and longitudinal resonance modes. It is found that the resonance intensity of the transversal modes (T-Modes) excited by the p- polarized wave is obviously larger than the intensity for the s- polarized wave at the wavelength of the transversal resonance, and the resonance intensity of the longitudinal modes (L-Modes) excited by the s- polarized wave is clearly larger than the intensity for the p- polarized wave at the longitudinal resonance wavelength, indicating a distinct polarization characteristics, which results from excitation of the different resonance modes of surface plasmons at different wavelengths. Moreover, the polarization behavior in near field regions for the different resonance modes has been demonstrated by the electric field distributions of the plasmonic nanorods based on FDTD simulation. In addition, the working wavelength of the polarizer can be tuned by the diameter and length of the silver nanorods in the visible spectral range, higher extinction ratios and lower insertion losses can be achieved based on the different resonance modes associated with the different polarizations. The polarizers will be a promising candidate for its potential applications in integration of nanophotonic devices.

Plasmonic nanorod metamaterials exhibit transversal and longitudinal resonance modes. It is found that the resonance intensity of the transversal modes (T-Modes) excited by the p- polarized wave is obviously larger than the intensity for the s- polarized wave at the wavelength of the transversal resonance, and the resonance intensity of the longitudinal modes (L-Modes) excited by the s- polarized wave is clearly larger than the intensity for the p- polarized wave at the longitudinal resonance wavelength, indicating a distinct polarization characteristics, which results from excitation of the different resonance modes of surface plasmons at different wavelengths. Moreover, the polarization behavior in near field regions for the different resonance modes has been demonstrated by the electric field distributions of the plasmonic nanorods based on FDTD simulation. In addition, the working wavelength of the polarizer can be tuned by the diameter and length of the silver nanorods in the visible spectral range, higher extinction ratios and lower insertion losses can be achieved based on the different resonance modes associated with the different polarizations. The polarizers will be a promising candidate for its potential applications in integration of nanophotonic devices.

Electrospinning is a very simple method of preparing polymer solutions into high performance fibers. In this work, PM597-doped polymer fibers with different diameters have been fabricated by electrospinning technology. Whispering gallery mode (WGM) lasing emission was observed when a 532 nm pulse laser beam radially excited the single electrospun polymer fiber (EPF) created by this method. The distribution of WGMs is also quantitatively confirmed through theoretical calculation. Additionally, the number of WGM laser peaks decrease as the diameter of the EPF decreases. Single longitudinal mode laser emission can be obtained when the EPF diameter decreases to 8.8m. It has also been found that the WGM laser from the single EPF has relatively low thresholds and good lifetime compared to droplet lasers or other fiber lasers. Moreover, EPF networks have unique research prospects in photonic devices, optical pump lasers and biosensing due to their very large surface to volume ratio.

Electrospinning is a very simple method of preparing polymer solutions into high performance fibers. In this work, PM597-doped polymer fibers with different diameters have been fabricated by electrospinning technology. Whispering gallery mode (WGM) lasing emission was observed when a 532 nm pulse laser beam radially excited the single electrospun polymer fiber (EPF) created by this method. The distribution of WGMs is also quantitatively confirmed through theoretical calculation. Additionally, the number of WGM laser peaks decrease as the diameter of the EPF decreases. Single longitudinal mode laser emission can be obtained when the EPF diameter decreases to 8.8m. It has also been found that the WGM laser from the single EPF has relatively low thresholds and good lifetime compared to droplet lasers or other fiber lasers. Moreover, EPF networks have unique research prospects in photonic devices, optical pump lasers and biosensing due to their very large surface to volume ratio.

Polarizers are one of the most fundamental elements used in optical devices. Compared with conventional prism polarizers, wire grid polarizers have potential for the miniaturization and integration of the optical devices. There are growing demands for design of the wire grid polarizers operating in a very broad spectral range from deep-ultraviolet to mid-infrared wavelengths. However, construction of the ultrabroadband polarizers based on the same structures and materials is very challenging. Here, ultrabroadband optical polarizers working in the deep-ultraviolet to mid-infrared spectral region, based on Al nanowire metamaterials with hexagonally packed nanowire arrays, are presented. To synchronously obtain high extinction ratios and low insertion losses, a q factor is found, when the q factor is fixed, the extinction ratio increases and the insertion loss simultaneously decreases with decreasing nanowire diameter. Moreover, the cut-off wavelength of the polarizers remarkably shifts to a much shorter wavelength when the refractive index of the surrounding medium decreases. Consequently, the polarizers demonstrate high performance operating down to the deep-ultraviolet spectral range based on an optimal design of the Al nanowire metamaterials embedded in air by selecting a smaller diameter (e.g. 15 nm) and a suitable q factor (e.g. 2 or 2.5).

Spin-glass theory has been widely introduced to describe the statistical behaviors in complex physical systems. By analogy between disorder photonics and other complex systems, the glassy behavior, especially the replica symmetry breaking (RSB) phenomenon, has been observed in random lasers. However, previous studies only analyzed the statistical properties of the random laser systems with single gain material. Here, the first experimental evidence of the glassy behavior in a random laser with complex energy level structure is reported. This novel random laser is demonstrated based on the electrospun polymer fibers with the assistance of Förster resonance energy transfer (FRET). The electrospinning technology employed in the experiment herein promises high-volume production of random laser devices with multiple energy levels, enabling the comprehensive investigation of lasing properties in multi-energy level random laser system. Clear paramagnetic phase and spin-glass phase are observed in the FRET-assisted random laser under different pump energies. The RSB phase transition is verified to occur at the laser threshold, which is robust among the random lasers with different donor–acceptor ratio. The finding of RSB in FRET-assisted random laser provides a new statistical analysis method toward the laser system with complex energy level, for example, quantum cascade laser.

Phenotypic profiling of single floating cells in liquid biopsies is the key to the era of precision medicine. A random laser in biofluids is a promising tool for the label-free characterization of the biophysical properties as a result of the high brightness and sharp peaks of the lasing spectra, yet previous reports were limited to the random laser in solid tissues with dense scattering. In this report, a random laser cytometer is demonstrated in an optofluidic device filled with gain medium and human breast normal/cancerous cells. The multiple lightscattering event induced by the microscale human cells promotes random lasing and influences the lasing properties in term of laser modes, spectral wavelengths, and lasing thresholds. A sensing strategy based on analyzing the lasing properties is developed to determine both the whole cell and the subcellular biophysical properties, and the malignant alterations of the cell suspensions are successfully detected. Our results provide a new approach to designing a label-free biophysical cytometer based on optofluidic random laser devices, which is advantageous for further research in the field of random laser bioapplication.

We have demonstrated the realization of a high-polarization random fiber laser (RFL) output based on the hybrid Raman and Erbium gain with the tailored effect provided by a 45°-tilted fiber Bragg grating (45°-TFBG), revealing an improvement in the polarization extinction ratio (PER) and achieving a PER of ~15.3 dB. The hybrid RFL system incorporating the 45°-TFBG has been systematically characterized. The random lasing wavelength can be fixed under the extremely weak feedback effect of the 45°-TFBG with reflectivity of 0.09%. In addition, numerical simulation has verified that the weak feedback can boost the random lasing emission with fixed wavelength using a power balance model, which is in good accordance with the experiment results.

Spin-glass theory has been widely introduced to describe the statistical behaviors in complex physical systems. By analogy between disorder photonics and other complex systems, the glassy behavior, especially the replica symmetry breaking (RSB) phenomenon, has been observed in random lasers. However, previous studies only analyzed the statistical properties of the random laser systems with single gain material. Here, the first experimental evidence of the glassy behavior in a random laser with complex energy level structure is reported. This novel random laser is demonstrated based on the electrospun polymer fibers with the assistance of Förster resonance energy transfer (FRET). The electrospinning technology employed in the experiment herein promises high-volume production of random laser devices with multiple energy levels, enabling the comprehensive investigation of lasing properties in multi-energy level random laser system. Clear paramagnetic phase and spin-glass phase are observed in the FRET-assisted random laser under different pump energies. The RSB phase transition is verified to occur at the laser threshold, which is robust among the random lasers with different donor–acceptor ratio. The finding of RSB in FRET-assisted random laser provides a new statistical analysis method toward the laser system with complex energy level, for example, quantum cascade laser.

Polarizers are one of the most fundamental elements used in optical devices. Compared with conventional prism polarizers, wire grid polarizers have potential for the miniaturization and integration of the optical devices. There are growing demands for design of the wire grid polarizers operating in a very broad spectral range from deep-ultraviolet to mid-infrared wavelengths. However, construction of the ultrabroadband polarizers based on the same structures and materials is very challenging. Here, ultrabroadband optical polarizers working in the deep-ultraviolet to mid-infrared spectral region, based on Al nanowire metamaterials with hexagonally packed nanowire arrays, are presented. To synchronously obtain high extinction ratios and low insertion losses, a q factor is found, when the q factor is fixed, the extinction ratio increases and the insertion loss simultaneously decreases with decreasing nanowire diameter. Moreover, the cut-off wavelength of the polarizers remarkably shifts to a much shorter wavelength when the refractive index of the surrounding medium decreases. Consequently, the polarizers demonstrate high performance operating down to the deep-ultraviolet spectral range based on an optimal design of the Al nanowire metamaterials embedded in air by selecting a smaller diameter (e.g. 15 nm) and a suitable q factor (e.g. 2 or 2.5).

We have demonstrated the realization of a high-polarization random fiber laser (RFL) output based on the hybrid Raman and Erbium gain with the tailored effect provided by a 45°-tilted fiber Bragg grating (45°-TFBG), revealing an improvement in the polarization extinction ratio (PER) and achieving a PER of ~15.3 dB. The hybrid RFL system incorporating the 45°-TFBG has been systematically characterized. The random lasing wavelength can be fixed under the extremely weak feedback effect of the 45°-TFBG with reflectivity of 0.09%. In addition, numerical simulation has verified that the weak feedback can boost the random lasing emission with fixed wavelength using a power balance model, which is in good accordance with the experiment results.

Phenotypic profiling of single floating cells in liquid biopsies is the key to the era of precision medicine. A random laser in biofluids is a promising tool for the label-free characterization of the biophysical properties as a result of the high brightness and sharp peaks of the lasing spectra, yet previous reports were limited to the random laser in solid tissues with dense scattering. In this report, a random laser cytometer is demonstrated in an optofluidic device filled with gain medium and human breast normal/cancerous cells. The multiple lightscattering event induced by the microscale human cells promotes random lasing and influences the lasing properties in term of laser modes, spectral wavelengths, and lasing thresholds. A sensing strategy based on analyzing the lasing properties is developed to determine both the whole cell and the subcellular biophysical properties, and the malignant alterations of the cell suspensions are successfully detected. Our results provide a new approach to designing a label-free biophysical cytometer based on optofluidic random laser devices, which is advantageous for further research in the field of random laser bioapplication.

Plasmonic nanorod metamaterials exhibit transversal and longitudinal resonance modes. It is found that the resonance intensity of the transversal modes (T-Modes) excited by the p- polarized wave is obviously larger than the intensity for the s- polarized wave at the wavelength of the transversal resonance, and the resonance intensity of the longitudinal modes (L-Modes) excited by the s- polarized wave is clearly larger than the intensity for the p- polarized wave at the longitudinal resonance wavelength, indicating a distinct polarization characteristics, which results from excitation of the different resonance modes of surface plasmons at different wavelengths. Moreover, the polarization behavior in near field regions for the different resonance modes has been demonstrated by the electric field distributions of the plasmonic nanorods based on FDTD simulation. In addition, the working wavelength of the polarizer can be tuned by the diameter and length of the silver nanorods in the visible spectral range, higher extinction ratios and lower insertion losses can be achieved based on the different resonance modes associated with the different polarizations. The polarizers will be a promising candidate for its potential applications in integration of nanophotonic devices.

Plasmonic nanorod metamaterials exhibit transversal and longitudinal resonance modes. It is found that the resonance intensity of the transversal modes (T-Modes) excited by the p- polarized wave is obviously larger than the intensity for the s- polarized wave at the wavelength of the transversal resonance, and the resonance intensity of the longitudinal modes (L-Modes) excited by the s- polarized wave is clearly larger than the intensity for the p- polarized wave at the longitudinal resonance wavelength, indicating a distinct polarization characteristics, which results from excitation of the different resonance modes of surface plasmons at different wavelengths. Moreover, the polarization behavior in near field regions for the different resonance modes has been demonstrated by the electric field distributions of the plasmonic nanorods based on FDTD simulation. In addition, the working wavelength of the polarizer can be tuned by the diameter and length of the silver nanorods in the visible spectral range, higher extinction ratios and lower insertion losses can be achieved based on the different resonance modes associated with the different polarizations. The polarizers will be a promising candidate for its potential applications in integration of nanophotonic devices.

Electrospinning is a very simple method of preparing polymer solutions into high performance fibers. In this work, PM597-doped polymer fibers with different diameters have been fabricated by electrospinning technology. Whispering gallery mode (WGM) lasing emission was observed when a 532 nm pulse laser beam radially excited the single electrospun polymer fiber (EPF) created by this method. The distribution of WGMs is also quantitatively confirmed through theoretical calculation. Additionally, the number of WGM laser peaks decrease as the diameter of the EPF decreases. Single longitudinal mode laser emission can be obtained when the EPF diameter decreases to 8.8m. It has also been found that the WGM laser from the single EPF has relatively low thresholds and good lifetime compared to droplet lasers or other fiber lasers. Moreover, EPF networks have unique research prospects in photonic devices, optical pump lasers and biosensing due to their very large surface to volume ratio.

Spin-glass theory has been widely introduced to describe the statistical behaviors in complex physical systems. By analogy between disorder photonics and other complex systems, the glassy behavior, especially the replica symmetry breaking (RSB) phenomenon, has been observed in random lasers. However, previous studies only analyzed the statistical properties of the random laser systems with single gain material. Here, the first experimental evidence of the glassy behavior in a random laser with complex energy level structure is reported. This novel random laser is demonstrated based on the electrospun polymer fibers with the assistance of Förster resonance energy transfer (FRET). The electrospinning technology employed in the experiment herein promises high-volume production of random laser devices with multiple energy levels, enabling the comprehensive investigation of lasing properties in multi-energy level random laser system. Clear paramagnetic phase and spin-glass phase are observed in the FRET-assisted random laser under different pump energies. The RSB phase transition is verified to occur at the laser threshold, which is robust among the random lasers with different donor–acceptor ratio. The finding of RSB in FRET-assisted random laser provides a new statistical analysis method toward the laser system with complex energy level, for example, quantum cascade laser.

Polarizers are one of the most fundamental elements used in optical devices. Compared with conventional prism polarizers, wire grid polarizers have potential for the miniaturization and integration of the optical devices. There are growing demands for design of the wire grid polarizers operating in a very broad spectral range from deep-ultraviolet to mid-infrared wavelengths. However, construction of the ultrabroadband polarizers based on the same structures and materials is very challenging. Here, ultrabroadband optical polarizers working in the deep-ultraviolet to mid-infrared spectral region, based on Al nanowire metamaterials with hexagonally packed nanowire arrays, are presented. To synchronously obtain high extinction ratios and low insertion losses, a q factor is found, when the q factor is fixed, the extinction ratio increases and the insertion loss simultaneously decreases with decreasing nanowire diameter. Moreover, the cut-off wavelength of the polarizers remarkably shifts to a much shorter wavelength when the refractive index of the surrounding medium decreases. Consequently, the polarizers demonstrate high performance operating down to the deep-ultraviolet spectral range based on an optimal design of the Al nanowire metamaterials embedded in air by selecting a smaller diameter (e.g. 15 nm) and a suitable q factor (e.g. 2 or 2.5).

Phenotypic profiling of single floating cells in liquid biopsies is the key to the era of precision medicine. A random laser in biofluids is a promising tool for the label-free characterization of the biophysical properties as a result of the high brightness and sharp peaks of the lasing spectra, yet previous reports were limited to the random laser in solid tissues with dense scattering. In this report, a random laser cytometer is demonstrated in an optofluidic device filled with gain medium and human breast normal/cancerous cells. The multiple lightscattering event induced by the microscale human cells promotes random lasing and influences the lasing properties in term of laser modes, spectral wavelengths, and lasing thresholds. A sensing strategy based on analyzing the lasing properties is developed to determine both the whole cell and the subcellular biophysical properties, and the malignant alterations of the cell suspensions are successfully detected. Our results provide a new approach to designing a label-free biophysical cytometer based on optofluidic random laser devices, which is advantageous for further research in the field of random laser bioapplication.

We have demonstrated the realization of a high-polarization random fiber laser (RFL) output based on the hybrid Raman and Erbium gain with the tailored effect provided by a 45°-tilted fiber Bragg grating (45°-TFBG), revealing an improvement in the polarization extinction ratio (PER) and achieving a PER of ~15.3 dB. The hybrid RFL system incorporating the 45°-TFBG has been systematically characterized. The random lasing wavelength can be fixed under the extremely weak feedback effect of the 45°-TFBG with reflectivity of 0.09%. In addition, numerical simulation has verified that the weak feedback can boost the random lasing emission with fixed wavelength using a power balance model, which is in good accordance with the experiment results.

Electrospinning is a very simple method of preparing polymer solutions into high performance fibers. In this work, PM597-doped polymer fibers with different diameters have been fabricated by electrospinning technology. Whispering gallery mode (WGM) lasing emission was observed when a 532 nm pulse laser beam radially excited the single electrospun polymer fiber (EPF) created by this method. The distribution of WGMs is also quantitatively confirmed through theoretical calculation. Additionally, the number of WGM laser peaks decrease as the diameter of the EPF decreases. Single longitudinal mode laser emission can be obtained when the EPF diameter decreases to 8.8m. It has also been found that the WGM laser from the single EPF has relatively low thresholds and good lifetime compared to droplet lasers or other fiber lasers. Moreover, EPF networks have unique research prospects in photonic devices, optical pump lasers and biosensing due to their very large surface to volume ratio.

Spin-glass theory has been widely introduced to describe the statistical behaviors in complex physical systems. By analogy between disorder photonics and other complex systems, the glassy behavior, especially the replica symmetry breaking (RSB) phenomenon, has been observed in random lasers. However, previous studies only analyzed the statistical properties of the random laser systems with single gain material. Here, the first experimental evidence of the glassy behavior in a random laser with complex energy level structure is reported. This novel random laser is demonstrated based on the electrospun polymer fibers with the assistance of Förster resonance energy transfer (FRET). The electrospinning technology employed in the experiment herein promises high-volume production of random laser devices with multiple energy levels, enabling the comprehensive investigation of lasing properties in multi-energy level random laser system. Clear paramagnetic phase and spin-glass phase are observed in the FRET-assisted random laser under different pump energies. The RSB phase transition is verified to occur at the laser threshold, which is robust among the random lasers with different donor–acceptor ratio. The finding of RSB in FRET-assisted random laser provides a new statistical analysis method toward the laser system with complex energy level, for example, quantum cascade laser.

Polarizers are one of the most fundamental elements used in optical devices. Compared with conventional prism polarizers, wire grid polarizers have potential for the miniaturization and integration of the optical devices. There are growing demands for design of the wire grid polarizers operating in a very broad spectral range from deep-ultraviolet to mid-infrared wavelengths. However, construction of the ultrabroadband polarizers based on the same structures and materials is very challenging. Here, ultrabroadband optical polarizers working in the deep-ultraviolet to mid-infrared spectral region, based on Al nanowire metamaterials with hexagonally packed nanowire arrays, are presented. To synchronously obtain high extinction ratios and low insertion losses, a q factor is found, when the q factor is fixed, the extinction ratio increases and the insertion loss simultaneously decreases with decreasing nanowire diameter. Moreover, the cut-off wavelength of the polarizers remarkably shifts to a much shorter wavelength when the refractive index of the surrounding medium decreases. Consequently, the polarizers demonstrate high performance operating down to the deep-ultraviolet spectral range based on an optimal design of the Al nanowire metamaterials embedded in air by selecting a smaller diameter (e.g. 15 nm) and a suitable q factor (e.g. 2 or 2.5).

Phenotypic profiling of single floating cells in liquid biopsies is the key to the era of precision medicine. A random laser in biofluids is a promising tool for the label-free characterization of the biophysical properties as a result of the high brightness and sharp peaks of the lasing spectra, yet previous reports were limited to the random laser in solid tissues with dense scattering. In this report, a random laser cytometer is demonstrated in an optofluidic device filled with gain medium and human breast normal/cancerous cells. The multiple lightscattering event induced by the microscale human cells promotes random lasing and influences the lasing properties in term of laser modes, spectral wavelengths, and lasing thresholds. A sensing strategy based on analyzing the lasing properties is developed to determine both the whole cell and the subcellular biophysical properties, and the malignant alterations of the cell suspensions are successfully detected. Our results provide a new approach to designing a label-free biophysical cytometer based on optofluidic random laser devices, which is advantageous for further research in the field of random laser bioapplication.

We have demonstrated the realization of a high-polarization random fiber laser (RFL) output based on the hybrid Raman and Erbium gain with the tailored effect provided by a 45°-tilted fiber Bragg grating (45°-TFBG), revealing an improvement in the polarization extinction ratio (PER) and achieving a PER of ~15.3 dB. The hybrid RFL system incorporating the 45°-TFBG has been systematically characterized. The random lasing wavelength can be fixed under the extremely weak feedback effect of the 45°-TFBG with reflectivity of 0.09%. In addition, numerical simulation has verified that the weak feedback can boost the random lasing emission with fixed wavelength using a power balance model, which is in good accordance with the experiment results.

Trapping light within cavities or waveguides in photonic crystals is an effective technology in modern integrated optics. Traditionally, cavities rely on total internal reflection or a photonic bandgap to achieve field confinement. Recent investigations have examined new localized modes that occur at a Dirac frequency that is beyond any complete photonic bandgap. We design Al2O3 dielectric cylinders placed on a triangular lattice in air, and change the central rod size to form a photonic crystal microcavity. It is predicted that waves can be localized at the Dirac frequency in this device without photonic bandgaps or total internal reflections. We perform a theoretical analysis of this new wave localization and verify it experimentally. This work paves the way for exploring localized defect modes at the Dirac point in the visible and infrared bands, with potential applicability to new optical devices.

A band-gap-tailored random laser with a wide tunable range and low threshold through infrared radiation is demonstrated. When fluorescent dyes are doped into the liquid crystal and heavily doped chiral agent system, we demonstrate a wavelength tuning random laser instead of a side-band laser, which is caused by the combined effect of multi-scattering of liquid crystal (LC) and band-gap control. Through rotating the infrared absorbing material on the side of the LC cell, an adjustable range for random lasing of 80 nm by infrared light irradiation was observed.

This paper systematically demonstrated a variety of experimental phenomena of random lasers (RLs) of N,N′-di-(3-(isobutyl polyhedral oligomeric silsesquioxanes)propyl) perylene diimide (DPP) organic/inorganic hybrid laser dye, which is composed of perylene diimide (PDI) as gain media and polyhedral oligomeric silsesquioxanes (POSS) as scattering media at a mole ratio of 1:2. In this work, we observe the transition from incoherent RL in the DPP-doped solutions and polymer membrane systems using dip-coating method to coherent RL in the polymer membrane system with defect waveguide using semi-polymerization (SP) coating method. Meanwhile, we found that the hybrid dye-DPP has a long lasing lifetime compared with the traditional laser dyes, which indicates that the POSS group can suppress the photo-bleaching effect to extend the working life of laser dyes.

This paper systematically demonstrated a variety of experimental phenomena of random lasers (RLs) of N,N′-di-(3-(isobutyl polyhedral oligomeric silsesquioxanes)propyl) perylene diimide (DPP) organic/inorganic hybrid laser dye, which is composed of perylene diimide (PDI) as gain media and polyhedral oligomeric silsesquioxanes (POSS) as scattering media at a mole ratio of 1:2. In this work, we observe the transition from incoherent RL in the DPP-doped solutions and polymer membrane systems using dip-coating method to coherent RL in the polymer membrane system with defect waveguide using semi-polymerization (SP) coating method. Meanwhile, we found that the hybrid dye-DPP has a long lasing lifetime compared with the traditional laser dyes, which indicates that the POSS group can suppress the photo-bleaching effect to extend the working life of laser dyes.

The stability of the scattering loop is fundamental for coherent random lasing in a dynamic scattering system. In this work, fluorescence of DPP (N, N-di [3-(isobutyl polyhedral oligomeric silsesquioxanes) propyl] perylene diimide) is scattered to produce RL and we realize the transition from incoherent RL to coherent RL by controlling the Brownian motion of the scatterers (dimer aggregates of DPP) and the stability of scattering loop. To produce coherent random lasers, the loop needs to maintain a stable state within the loop-stable time, which can be determined through controlled Brownian motion of scatterers in the scattering system. The result shows that the loop-stable time is within 5.83 × 10−5 s to 1.61 × 10−4 s based on the transition from coherent to incoherent random lasing. The time range could be tuned by finely controlling the viscosity of the solution. This work not only develops a method to predict the loop-stable time, but also develops the study between Brownian motion and random lasers, which opens the road to a variety of novel interdisciplinary investigations involving modern statistical mechanics and disordered photonics.

The stability of the scattering loop is fundamental for coherent random lasing in a dynamic scattering system. In this work, fluorescence of DPP (N, N-di [3-(isobutyl polyhedral oligomeric silsesquioxanes) propyl] perylene diimide) is scattered to produce RL and we realize the transition from incoherent RL to coherent RL by controlling the Brownian motion of the scatterers (dimer aggregates of DPP) and the stability of scattering loop. To produce coherent random lasers, the loop needs to maintain a stable state within the loop-stable time, which can be determined through controlled Brownian motion of scatterers in the scattering system. The result shows that the loop-stable time is within 5.83 × 10−5 s to 1.61 × 10−4 s based on the transition from coherent to incoherent random lasing. The time range could be tuned by finely controlling the viscosity of the solution. This work not only develops a method to predict the loop-stable time, but also develops the study between Brownian motion and random lasers, which opens the road to a variety of novel interdisciplinary investigations involving modern statistical mechanics and disordered photonics.

A band-gap-tailored random laser with a wide tunable range and low threshold through infrared radiation is demonstrated. When fluorescent dyes are doped into the liquid crystal and heavily doped chiral agent system, we demonstrate a wavelength tuning random laser instead of a side-band laser, which is caused by the combined effect of multi-scattering of liquid crystal (LC) and band-gap control. Through rotating the infrared absorbing material on the side of the LC cell, an adjustable range for random lasing of 80 nm by infrared light irradiation was observed.

Trapping light within cavities or waveguides in photonic crystals is an effective technology in modern integrated optics. Traditionally, cavities rely on total internal reflection or a photonic bandgap to achieve field confinement. Recent investigations have examined new localized modes that occur at a Dirac frequency that is beyond any complete photonic bandgap. We design Al2O3 dielectric cylinders placed on a triangular lattice in air, and change the central rod size to form a photonic crystal microcavity. It is predicted that waves can be localized at the Dirac frequency in this device without photonic bandgaps or total internal reflections. We perform a theoretical analysis of this new wave localization and verify it experimentally. This work paves the way for exploring localized defect modes at the Dirac point in the visible and infrared bands, with potential applicability to new optical devices.

This paper systematically demonstrated a variety of experimental phenomena of random lasers (RLs) of N,N′-di-(3-(isobutyl polyhedral oligomeric silsesquioxanes)propyl) perylene diimide (DPP) organic/inorganic hybrid laser dye, which is composed of perylene diimide (PDI) as gain media and polyhedral oligomeric silsesquioxanes (POSS) as scattering media at a mole ratio of 1:2. In this work, we observe the transition from incoherent RL in the DPP-doped solutions and polymer membrane systems using dip-coating method to coherent RL in the polymer membrane system with defect waveguide using semi-polymerization (SP) coating method. Meanwhile, we found that the hybrid dye-DPP has a long lasing lifetime compared with the traditional laser dyes, which indicates that the POSS group can suppress the photo-bleaching effect to extend the working life of laser dyes.

The stability of the scattering loop is fundamental for coherent random lasing in a dynamic scattering system. In this work, fluorescence of DPP (N, N-di [3-(isobutyl polyhedral oligomeric silsesquioxanes) propyl] perylene diimide) is scattered to produce RL and we realize the transition from incoherent RL to coherent RL by controlling the Brownian motion of the scatterers (dimer aggregates of DPP) and the stability of scattering loop. To produce coherent random lasers, the loop needs to maintain a stable state within the loop-stable time, which can be determined through controlled Brownian motion of scatterers in the scattering system. The result shows that the loop-stable time is within 5.83 × 10−5 s to 1.61 × 10−4 s based on the transition from coherent to incoherent random lasing. The time range could be tuned by finely controlling the viscosity of the solution. This work not only develops a method to predict the loop-stable time, but also develops the study between Brownian motion and random lasers, which opens the road to a variety of novel interdisciplinary investigations involving modern statistical mechanics and disordered photonics.

A band-gap-tailored random laser with a wide tunable range and low threshold through infrared radiation is demonstrated. When fluorescent dyes are doped into the liquid crystal and heavily doped chiral agent system, we demonstrate a wavelength tuning random laser instead of a side-band laser, which is caused by the combined effect of multi-scattering of liquid crystal (LC) and band-gap control. Through rotating the infrared absorbing material on the side of the LC cell, an adjustable range for random lasing of 80 nm by infrared light irradiation was observed.

Trapping light within cavities or waveguides in photonic crystals is an effective technology in modern integrated optics. Traditionally, cavities rely on total internal reflection or a photonic bandgap to achieve field confinement. Recent investigations have examined new localized modes that occur at a Dirac frequency that is beyond any complete photonic bandgap. We design Al2O3 dielectric cylinders placed on a triangular lattice in air, and change the central rod size to form a photonic crystal microcavity. It is predicted that waves can be localized at the Dirac frequency in this device without photonic bandgaps or total internal reflections. We perform a theoretical analysis of this new wave localization and verify it experimentally. This work paves the way for exploring localized defect modes at the Dirac point in the visible and infrared bands, with potential applicability to new optical devices.

The stability of the scattering loop is fundamental for coherent random lasing in a dynamic scattering system. In this work, fluorescence of DPP (N, N-di [3-(isobutyl polyhedral oligomeric silsesquioxanes) propyl] perylene diimide) is scattered to produce RL and we realize the transition from incoherent RL to coherent RL by controlling the Brownian motion of the scatterers (dimer aggregates of DPP) and the stability of scattering loop. To produce coherent random lasers, the loop needs to maintain a stable state within the loop-stable time, which can be determined through controlled Brownian motion of scatterers in the scattering system. The result shows that the loop-stable time is within 5.83 × 10−5 s to 1.61 × 10−4 s based on the transition from coherent to incoherent random lasing. The time range could be tuned by finely controlling the viscosity of the solution. This work not only develops a method to predict the loop-stable time, but also develops the study between Brownian motion and random lasers, which opens the road to a variety of novel interdisciplinary investigations involving modern statistical mechanics and disordered photonics.

A band-gap-tailored random laser with a wide tunable range and low threshold through infrared radiation is demonstrated. When fluorescent dyes are doped into the liquid crystal and heavily doped chiral agent system, we demonstrate a wavelength tuning random laser instead of a side-band laser, which is caused by the combined effect of multi-scattering of liquid crystal (LC) and band-gap control. Through rotating the infrared absorbing material on the side of the LC cell, an adjustable range for random lasing of 80 nm by infrared light irradiation was observed.