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In this paper, we investigated tunable lasing properties from the dye-doped holographic polymer dispersed liquid crystal (HPDLC) gratings in capillaries with thermal and optical manners. The thermally tunable range of the lasing from the dye-doped HPDLC reached 8.60 nm with the temperature ranging from 23 °C to 50 °C. The optically tunable laser emission was achieved by doping azo-dye in HPDLC. The transition of azo-dye from trans- to cis-state could induce the reorientation of LC molecules after UV light irradiation, which resulted in the variation of refractive index contrast of LC-rich/polymer-rich layer in HPDLC. Experimentally, the emission wavelength of lasing showed a blueshift (about 2 nm) coupled with decreasing output intensities. The tunable laser based on HPDLC may enable more applications in laser displays, optical communication, biosensors, etc. [ABSTRACT FROM AUTHOR]

A kind of blue phase liquid crystal (BPLC), consisting of nematic liquid crystal, E7, and chiral dopants, CB15 and R1011, was investigated by doping PbS nanoparticles. The blue phase temperature range was extended from 3oC to 4.6°C by doping PbS nanoparticles with diameters around 9.6 nm. A kind of porous texture was observed both in the forming process of PbS nanoparticles doped BPLCs as well as in the BPLCs (with/without PbS nanoparticles) under assisting electric field. The porous texture may indicate that the liquid crystals molecule should be reoriented during the formation process of PbS nanoparticles doped BPLCs. [ABSTRACT FROM AUTHOR]

Abstract: We examined the focusing properties of fractal zone plates (FraZPs) in detail based on a liquid crystal on silicon (LCOS) spatial light modulator (SLM). It was shown that the focal length shifted linearly when the lacunarity of first order FraZPs experienced a linear displacement. From the theoretical analysis and the experimental results, we showed the potential to use the FraZPs as a focusing element whose focal length can be tuned finely. In addition, some side effects of this element were also discussed. [Copyright &y& Elsevier]

The working models of LCoS (Liquid Crystal on Silicon) were optimized in parameter space by simulation. Two modes were selected, which were suitable for phase modulation. One was the RTN-52° mode, the other was parallel alignment ECB mode. Phase changes were measured when various voltages are applied to LCoS. In addition, we showed some results when the LCoS was used as a Fresnel lens. [Copyright &y& Elsevier]

• A pixelated polarization calibration approach is proposed to enable efficient and precise programming of spatially-varying linearly polarized light. • The proposed approach is further verified by the implementation of the Pancharatnam-Berry (PB) lens with the focusing efficiency of 85.58 % for the circularly polarized light. The resolution of the fabricated LC planar optical elements with the proposed setup can reach 1.54 μm. • The proposed liquid crystal spatial light modulator (LC-SLM)-based exposure system can enable arbitrary alignment patterns fabrication for LC molecules with only one single exposure step, providing great potential for vectorial light field generation and LC-based planar optics. The use of liquid crystal spatial light modulator (LC-SLM) to manipulate the polarization of the light has been widely explored for different applications, including optical field manipulation, maskless lithography, polarization imaging, and LC planar-optics, among others. Precise polarization manipulation of LC-SLM is therefore highly demanded. Here, we introduce a high-efficiency approach for calibrating the polarization manipulation of a parallel-aligned LC-SLM. The approach revolves around the primary calibration criterion, the degree of polarization (DoP). Through parameter optimization to generate the calibration grayscale, a remarkable DoP as high as 97 % can be attained, with a sustained DoP level of up to 93.7 %. Experimental results showcase outstanding DoP uniformity in the modulated beam achieved with the calibrated LC-SLM. The root mean square error (RMSE) of polarization for modulated light from LC-SLM is about 0.018. A pixelated polarization calibration approach is proposed to enable efficient and precise programming of spatially-varying linearly polarized light (SVLPL), which can be further verified by the implementation of the Pancharatnam-Berry (PB) lens. The resolution of the fabricated LC planar optical elements with our setup can reach 1.54 μm. The programmable SVLPL with high DoP and resolution is potentially useful for many applications in planar optics and vectorial optical field manipulation. [ABSTRACT FROM AUTHOR]

A highly sensitive cholic acid biosensor based on 4-cyano-4′-penthlbiphenyl (5CB) Liquid crystal droplets in phosphate buffer saline solution was reported. A radial-to-bipolar transition of 5CB droplet would be triggered during competitive reaction of CA at the sodium dodecyl sulfate surfactant-laden 5CB droplet surface. Our liquid crystal droplet sensor is a low-cost, simple and fast method for CA detection. The detection limit (5 μM) of our method is 2.4 times lower than previously report by using liquid crystal film to detection of CA. [ABSTRACT FROM AUTHOR]