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Terahertz polarization beam splitter based on photonic crystal and multimode interference

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Optoelectronics Letters 2014年第5期10卷 325-328页

作者：刘汉李九生 Centre for Terahertz Research China Jiliang University

We design a compact terahertz(THz) polarization beam splitter. Both plane wave expansion method and finite-difference time-domain method are used to calculate and analyze the characteristics of the proposed device. The designed polarization beam splitter can split TE-polarized and TM-polarized THz waves into different propagation directions. The simulation results show that the extinction ratios are larger than 18.36 dB for TE polarization and 13.35 dB for TM polarization in the frequency range from 1.86 THz to 1.91 THz, respectively. The designed polarization beam splitter has the advantages of small size and compact structure with a total size of 4.825 mm×0.400 mm.

关键词： Finite difference time domain method optical instruments Photonic crystals Prisms Time domain analysis

Broadband polarization beam splitter based on a negative refractive lithium niobate photonic crystal slab

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Chinese Optics Letters 2016年第4期14卷 69-72页

作者：段斯琪陈玉萍李广珍朱传义陈险峰 Department of Physics and Astronomy Shanghai Jiao Tong UniversityState Key Laboratory of Advanced Optical Communication Systems and Networks

Using a lithium niobate （LN） material, we propose a broadband polarization beam splitter （PBS） with high efficiency by employing a negative refractive photonic crystal （PhC） wedge slab with an angle of 60°. It can split the incident light into two parts at about 90° with TE and TM polarizations. The transmissions of polarized light for an LN-based PBS are more than 80% with a broad angle and wavelength bandwidth of 8° and 70 nm at 1.55μm, while with a Si-based PhC, no PBS with high efficiency can be realized for the relatively lower transmission of TM output light.

关键词： Efficiency Light sources Niobium compounds optical instruments Photonic crystals Polarization Prisms Refractive index

Real-time measurement of retardation of eighth-wave plate independent of fast-axis direction

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Chinese Optics Letters 2012年第9期10卷 35-37页

作者：方瑞芳曾爱军刘龙海朱玲琳黄惠杰 Shanghai Institute of Optics and Fine Mechanics Chinese Academy of Sciences Graduate University of Chinese Academy of Sciences

A real-time measurement method for the retardation of an eighth-wave plate is proposed. The collimated laser beam is split using a Clan Taylor polarizer with two side escape windows. The reflected sub-beam is detected using a detector, whereas the transmitted sub-beam passes through the quarter-wave plate and the eighth-wave plate of interest. Then, it is reflected by the mirror and passes reversely through the eighth- and quarter-wave plates. Finally, it is analyzed using the Clan Taylor polarizer and detected using another detector. With two detection signals, the retardation is resolved and found to be independent of the fast-axis direction, initial intensity, and circuit parameters. In the experiment, a crystal quartz sample is measured at different fast-axis angles. The standard deviation of the retardation is 0.9°. The usefulness of the method is verified.

关键词： optical instruments Quartz Time measurement

Compact beam splitters based on self-imaging phenomena in one-dimensional photonic crystal waveguides

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Chinese Optics Letters 2012年第11期10卷 28-31页

作者：陈兵黄琳李永东刘纯亮刘贵忠 Key Laboratory of Physical Electronics and Devices of the Ministry of Education Xi'an Jiaotong University Institute of Information and Communication Engineering Xi'an Jiaotong University

A fundamental 1× 2 beam splitter based on the self-imaging phenomena in multi-mode one-dimensional （1D） photonic crystal （PC） waveguides is presented, and its transmission characteristics are investigated using the finite-difference time-domain method. Calculated results indicate that a high transmittance （〉95%） can be observed within a wide frequency band for the 1×2 beam splitter without complicated structural optimizations. In this letter, a simple and compact 1×4 beam splitter is constructed by combining the fundamental 1×2 beam splitter with the flexible bends of 1D PC waveguides. Such beam splitters can be applied to highly dense photonic integrated circuits.

关键词： Finite difference time domain method Frequency bands Laser optics optical instruments optical waveguides Photonic crystals Structural optimization Time domain analysis Waveguides

Design of transverse magnetic-reflected polarizing f ilm

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Chinese Optics Letters 2014年第5期12卷 76-78页

作者：李松权高来勖刘书钢柳春郁黄妍叶红安 School of Electronic Engineering Heilongjiang University

We propose a wideband transverse magnetic-reflected polarizing film composed of Cr and SiO2. Based on the polarization characteristics of reflected light from Cr/SiO2 film, the film can serves as a polarizer to severely attenuate the transverse electric （TE）-polarized light and reflect the transverse magnetic （TM）- polarized light in a wavelength range from 600 to 900 nm. By suitably choosing the film thicknesses, the operation angles of such polarizers can be adjusted over a wide angle range greater than the critical angle of total reflection. Cr/SiO2 film has potential use in surface plasmon resonance （SPR） sensors based on Kretchmann configuration to form integrated structures.

关键词： Light polarization optical instruments Surface plasmon resonance