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Author

Xinglong Wang

Bio: Xinglong Wang is an academic researcher from Tianjin University. The author has contributed to research in topics: Birefringence. The author has an hindex of 1, co-authored 1 publications receiving 43 citations.
Topics: Birefringence

Papers
More filters
Journal ArticleDOI
TL;DR: Transmission formulas and transmission curves of birefringent filters when the optic axis is not in the plane of the filter plates are given and discussed in detail and this is the first design in a tunable laser pumped by a quasi-cw source.
Abstract: Transmission formulas and transmission curves of birefringent filters when the optic axis is not in the plane of the filter plates are given and discussed in detail. The optimum parameters of birefringent filters, such as the most suitable ratio of thicknesses, tuning angles, and plate thicknesses, are obtained. As far as we know this is the first design of birefringent filters used in a tunable laser pumped by a quasi-cw source.

47 citations


Cited by
More filters
Proceedings ArticleDOI
TL;DR: In this article, a new polarization-independent, liquid crystal (LC) spatial light modulator (SLM) based on a periodic nematic director profile is proposed, which acts as a switchable diffraction grating with only 0th and ± 1st orders at efficiencies of ≥ 99%.
Abstract: We report our recent experimental results on a new polarization-independent, liquid crystal (LC) spatial light modulator (SLM) Based on a periodic nematic director profile, the modulator acts as a switchable diffraction grating with only 0th- and ±1st-orders at efficiencies of ≥ 99%, manifests contrast ratios ~600:1 (for laser light), switching times of ~2ms, and threshold voltages of < 1V/μm Results of modulating broadband, unpolarized light from light-emitting-diodes (LEDs) indicates that contrast ratios are ~100:1 so far Note that incoherent scattering for visible light is very low, and that samples are typically completely defect-free over large areas An important feature of this diffractive polarization-independent SLM compared to its predecessors is its potential to achieve much larger diffraction angles, which enables a larger aperture (and etendue) In addition to describing the fabrication and characteristics of this SLM in general, we report on our initial progress in implementing a projection display system All of the surprising and useful results from this grating arise from its continuous nematic director, which is most properly classed as a switchable polarization grating (PG) The SLM described here offers the inherent advantages polarization-independence at the pixel-level and fairly fast switching with nematic LCs, while maintaining similar switching voltages, cell thickness, contrast ratios, and materials

73 citations

Journal ArticleDOI
TL;DR: In this paper, a complete, systematic methodology is provided for calculating all properties of the transmitted and reflected light waves, including phase-velocity indices of refraction, angles of reflection and reflection, polarization angles, walk-off angles, and Poynting-vector relative magnitudes.
Abstract: The general case of monochromatic plane-wave reflection and refraction at oblique incidence from a planar biaxial–biaxial interface is presented for arbitrary principal-axes orientation in each region. A complete, systematic methodology is provided for calculating all properties of the transmitted and reflected light waves. The singularities that arise when one or both regions are taken to be isotropic are addressed, to our knowledge for the first time. Example calculations are presented for all cases. Finally, the methodology yields all wave parameters, including phase-velocity indices of refraction, angles of refraction and reflection, polarization angles, walk-off angles, and Poynting-vector relative magnitudes. Some common applications of this theory include multilayer structure analysis and the determination of internal angles for second-harmonic generation.

54 citations

Journal ArticleDOI
TL;DR: A Lyot-Ohman filter for imaging near the solar He i 1083-nm line is described, and a first-light He i image of the Sun is presented.
Abstract: A Lyot–Ohman filter for imaging near the solar He i 1083-nm line is described. Fast and continuous spectral tunability is provided by nematic liquid crystals. This solid-state filter has a free spectral range of 2.35 nm and a spectral resolution of 0.135 nm at the operating wavelength of 1083 nm. A wide-fielded design was used for both static and electro-optic retarder elements, facilitating use in fast imaging systems. A first-light He i image of the Sun is presented.

42 citations

Journal ArticleDOI
TL;DR: This study is the first detailed investigation and experimental demonstration of birefringent filters with tilted optical axis for multicolor operation of solid-state lasers and it is suggested that implementation of tilted-axis BRFs should boost development of efficient and low-costMulticolor lasers in other gain media as well.
Abstract: In this study, we numerically and experimentally investigate application of birefringent filters (BRFs) as frequency selective elements in multicolor lasers. A BRF plate made out of crystalline quartz with an arbitrarily oriented optical axis has been explored. Simulation results have shown that compared to regular BRFs where the optical axis lies in the plane of the plates surface, a BRF with an optical axis pointing out of its surface enables design flexibility in filter parameters, providing access to a wider set of free spectral range and bandwidth values. As a result, multicolor operation could be obtained in many wavelength pairs using a single BRF plate. In the experiments a 3-mm thick quartz BRF with an optical axis 45° to the surface plane has been used. With Cr:Nd:GSGG as a laser medium two-color and three-color cw laser operation has been demonstrated in 11 and 3 different transition combinations, respectively. Moreover, two-color laser operation has been demonstrated in 10 different wavelength pairs in Cr:LiSAF. To our knowledge, this study is the first detailed investigation and experimental demonstration of BRFs with tilted optical axis for multicolor operation of solid-state lasers. Compared to other methods, BRFs enable a rich selection of transition pairs and also the ratio of the power in each line could be regulated by fine adjustment of the rotation angle. Implementation of tilted-axis BRFs should boost development of efficient and low-cost multicolor lasers in other gain media as well.

37 citations

Journal ArticleDOI
TL;DR: It is shown that a magnesium fluoride BRF with an optic axis diving by 30° into the plate could provide smooth tuning of ultra-broad laser gain media and have the potential to be useful in tuning of broadband lasers in continuous-wave, long-pulsed, and femtosecond operation regimes.
Abstract: Transition metal-doped gain media, such as Ce:LiCAF, Ti:sapphire, Cr:ZnSe, and Fe:ZnSe, possess wide gain bandwidths that could provide ultra broadly tunable laser output with the usage of adequate intracavity tuning elements. Birefringent filters (BRFs) are a low-cost and easy to use solution for tuning. However, for ultrabroad gain media, regular on-surface optic axis BRFs could not provide smooth tuning of laser wavelength in the whole emission range. Basically, regular BRFs could not accommodate a large enough free spectral range with acceptable modulation depth variation while tuning, due to their slow tuning rates. Motivated by this, in this study, we have numerically investigated the effect of optic axis orientation on filter parameters for magnesium fluoride birefringent tuning plates. We have shown that a magnesium fluoride BRF with an optic axis diving by 30° into the plate could provide smooth tuning of ultra-broad laser gain media. A similar analysis has shown that for broadband tuning applications, the optimum optic axis diving angle lies around 25° for crystal quartz BRFs. The proposed filters have the potential to be useful in tuning of broadband lasers in continuous-wave, long-pulsed, and femtosecond operation regimes.

30 citations