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Abstract Reconfigurable modular microfluidics presents an opportunity for flexibly constructing prototypes of advanced microfluidic systems. Nevertheless, the strategy of directly integrating modules cannot easily fulfill the requirements of common applications, e.g., the incorporation of materials with biochemical compatibility and optical transparency and the execution of small batch production of disposable chips for laboratory trials and initial tests. Here, we propose a manufacturing scheme inspired by the movable type printing technique to realize 3D free-assembly modular microfluidics. Double-layer 3D microfluidic structures can be produced by replicating the assembled molds. A library of modularized molds is presented for flow control, droplet generation and manipulation and cell trapping and coculture. In addition, a variety of modularized attachments, including valves, light sources and microscopic cameras, have been developed with the capability to be mounted onto chips on demand. Microfluidic systems, including those for concentration gradient generation, droplet-based microfluidics, cell trapping and drug screening, are demonstrated. This scheme enables rapid prototyping of microfluidic systems and construction of on-chip research platforms, with the intent of achieving high efficiency of proof-of-concept tests and small batch manufacturing.

In this study, aiming to extend the power of LG _01 -mode vortex light at 632.8 nm, the commercial He–Ne laser was upgraded to dual-tube gain geometry with the assistance of an intracavity spot defect for spatial filtering. We investigated the impact of using single and double He–Ne gas gain tubes on the powers of vortex laser output, and achieved a maximum 4.7 mW power of LG _01 -mode vortex light, corresponding to an optical–optical conversion efficiency of 39.2% and making it the highest power of vortex light obtained in He–Ne laser up to now.

In this research, a 1064 nm single-longitudinal-mode (SLM) vortex beam was generated from an annular-pumped Nd:YVO _4 microchip laser, in which a circular Dammann grating was used to reshape the 808 nm pump light into an annular intensity profile. As a result, the laser emitted a SLM LG _01 beam with a maximum output power of 192 mW. A straightforward technique for producing SLM vortex beams is made available by this work.

In this paper, we demonstrate a digital micromirror device (DMD) based optical microscopic apparatus for quantitative differential phase contrast (qDIC) imaging, coherent structured illumination microscopy (SIM), and dual-modality (scattering/fluorescent) imaging. For both the qDIC imaging and the coherent SIM, two sets of fringe patterns with orthogonal orientations and five phase-shifts for each orientation, are generated by a DMD and projected on a sample. A CCD camera records the generated images in a defocusing manner for qDIC and an in-focus manner for coherent SIM. Both quantitative phase images and super-resolved scattering/fluorescence images can be reconstructed from the recorded intensity images. Moreover, fluorescent imaging modality is integrated, providing specific biochemical structures of the sample once using fluorescent labeling.

By introducing a circular Dammann grating (CDG) into the pump unit, we demonstrated an endpumped Nd:YAG laser that emitted a vortex and first-order LG mode with high laser efficiency and high power. In our scheme, the CDG was used to reshape the pumping light into an annular profile, and the adaptation of it was realized easily by inserting it into the pump unit of a conventional end-pumped solid-state laser; the laser cavity was simple, compact, and consisted of only a laser crystal and an output coupler. The beam power of this laser reached 1.86 W at an absorbed pump power of 6.38 W with a slope efficiency of 34.5%. [ABSTRACT FROM AUTHOR]

A photorefractive hologram can be fixed locally under a temperature nonuniform field by CO2 laser heating the LiNbO3. Here, on the basis of analyzing the relationship between the fixed space-charge field amplitude Esc and the fixing temperature Tf, two parameters, the localization coefficient Ψ and the average space-charge field amplitude Escave, are defined to evaluate the fixed local photorefractive hologram by CO2 laser heating the LiNbO3. The same analysis also can be used when the boundary conditions and the laser beam profile are changed. © 2000 John Wiley & Sons, Inc. Microwave Opt Technol Lett 26: 89–93, 2000. [ABSTRACT FROM AUTHOR]

The transient interaction between a refraction index grating and light beams during simultaneous writing and thermal fixing of a photorefractive hologram is investigated. With a diffusion- and photovoltaic-dominated carrier transport mechanism and carrier thermal activation (temperature dependent) considered in Fe:LiNbO3 crystal, from the standpoint of field–material coupling, the theoretical thermal fixing time and the space-charge field buildup, spatial distribution, and temperature dependence are given numerically by combining the band transport model with mobile ions with the coupled-wave equation. ©1999 John Wiley & Sons, Inc. Microwave Opt Technol Lett 23: 372–376, 1999. [ABSTRACT FROM AUTHOR]

A simulated annealing algorithm is adopted to give an automatic pump configuration in laser-diode backward-pumped-distributed fiber Raman amplifiers. The demonstration of the optimization process of wavelengths and powers in an optical-fiber Raman amplifier using four laser-diode pumps is presented. The resulting gain ripple is less than 2.6 dB in respect to the 30 dB average gain in the amplification bandwidth of more than 50 nm (64 signal channels). The algorithm can be practically applied to the desired signal channel number and gain profile [ABSTRACT FROM PUBLISHER]

In distributed optical fiber Raman amplifiers, instantaneous pump power depletion is related to the patterns of the input wavelength-division-multiplexing signals, especially for high bit rate application. This results in additional optical noise and interchannel crosstalk. We analyzed the phenomenon and presented simulation results. The cases for different bit rates and channel numbers were compared [ABSTRACT FROM PUBLISHER]

In this paper, we demonstrated a passive Q-switched ytterbium-doped fiber laser with radially polarized beam emission by using a c-cut YVO4 birefringent crystal as the intracavity polarization discriminator, and a Cr4+:YAG crystal as the saturable absorber and output coupler. The maximum averaged laser power reached 3.89 W with a high slope efficiency of 66.5%. The laser pulse had a peak power of 161 W, 160 ns duration, and 151 kHz repetition rate at the absorbed pump power of 6.48 W. Such a radially polarized pulse would facilitate numerous applications. [ABSTRACT FROM AUTHOR]

We demonstrated an end-pumped and phase-locked Nd:YVO4 laser with 2  ×  2 arrayed output. In our scheme, the pump radiation from a laser diode were reshaped into 2  ×  2 arrays by a Dammann grating and induced four independent pumping areas in a monolithic Nd:YVO4 crystal. The 2  ×  2 arrayed laser beams emitted from this laser were phase locked due to the coupling of evanescent fields of these transverse modes. It was found that the phase difference between modes could be predicted by the minimization of the coherently coupled intensity between adjacent arrays. [ABSTRACT FROM AUTHOR]