Design of form-birefringent multilayer nonpolarizing beam splitter

Nonpolarizing beam splitters, which are based on the form birefringence of subwavelength multilayer binary gratings, have been proposed. The design is based on effective-medium theory and thin-film theory. Rigorous coupled-wave analysis is used to optimize the design of this nonpolarizing beam splitter. The simulation shows that the structure can eliminate polarization effect and provide high reflectivity.     

Deep silicon grating as high-extinction-ratio polarizing beam splitter

A deep binary silicon grating as high-extinction-ratio reflective polarizing beam splitter （PBS） at the wavelength of 1550 nm is presented. The design is based on the phenomenon of total internal reflection （TIR） by using the rigorous coupled wave analysis （RCWA）. The extinction ratio of the rectangular PBS grating can reach 2.5~105 with the optimum grating period of 397 nm and groove depth of 1.092 μm. The efficiencies of TM-polarized wave in the 0th order and TE-polarized wave in the -1st order can both reach unity at the Littrow angle. Holographic recording technology and inductively coupled plasma （ICP） etching could be used to fabricate the silicon PBS grating.     

Reflecting polarizing beam splitter

We propose and experimentally demonstrate the use of metal-covered lamellar relief gratings as a polarizing beam splitter operating at a single wavelength near Littrow incidence. We report the characteristics of a grating produced by holography and reactive ion etching that was calculated for operation as beam splitter at lambda = 633 nm (for a He-Ne laser).     

The design of a polarizing beam splitter made from a dielectric rectangular-groove grating

It has been reported that a polarizing beam splitter based on a rectangular-groove grating (a grating polarizing beam splitter) can be easily designed for specific applications using the modal method. In this paper, the eigenvalue equation of the modal method is transformed to a new form. Using this new form of the eigenvalue equation, it is shown that the design of a grating polarizing beam splitter can be independent of the incident wavelength. The period and the groove depth can be designed using values normalized to the incident wavelength, which apply to a range of wavelengths as long as the effects of dispersion can be neglected. Numerical simulations of fused silica gratings are presented and analyzed. It is concluded that the preferable choice for the grating period is 0.8–0.9 times the incident wavelength.     

Broadband polarizing beam splitter based on the form birefringence of a subwavelength grating in the quasi-static domain

We propose a novel broadband polarizing beam splitter with a compact sandwich structure that has a subwavelength grating in the quasi-static domain as the filling. The design is based on effective-medium theory an anisotropic thin-film theory, and the performance is investigated with rigorous coupled-wave theory. The design results show that the structure can provide a high polarization extinction ratio in a broad spectral range.     

Polarizing beam splitter based on a double-layer subwavelength grating

A Si–ZnS double-layer subwavelength grating is theoretically used as a high-efficient polarizing beam splitter. To design this structure, the rigorous coupled-wave analysis (RCWA) is applied to study the reflectivity and transmissivity for the TE and TM polarization, respectively. Simulation results show that both the zero-order reflection for TE polarization and the zero-order transmission for TM polarization can exceed 90% in a wide tunable working incident angle range from 48° to 72°. Moreover, the proposed polarizing beam splitter has a working wavelength that is in the range of 1500–1600 nm.     

Terahertz Brewster polarizing beam splitter on a polymer substrate

The performance of a terahertz （THz） Brewster polarizing beam splitter on polymer substrate is studied theoretically and experimentally. Simulations by using finite-element method demonstrate that both trans- nqittance/rei%ctanee and their extinction ratios are better than its 45 °counterpart in a broad frequency range. Especially, the reflection extinction ratio improves significantly. The results are also verified exper- imentally with THz time domain spectroscopy （TDS） and backward wave oscillator （BWO） measurement system.     

Connecting-layer-based polarizing beam splitter grating with high efficiency for both TE and TM polarizations

We describe a novel polarizing beam splitter (PBS) of transmission connecting-layer-based grating, which can show high efficiency for TE polarization in the ?1st order and TM polarization in the 0th order. According to the modal method, grating duty cycle and period are prescribed to obtain high efficiency for TM polarization. Using the rigorous coupled-wave analysis, grating depth and thickness of the connecting layer are optimized to achieve high efficiency for TE polarization. The presented PBS has advantages of wideband properties for incident wavelength and angle. Most importantly, the efficiency is improved greatly for TE polarization compared with the reported PBS based on fused-silica grating.     

Broad band polarizing beam splitter with a dielectric layer embedded in the groove of metal grating

We described the use of a metal grating embedded with a dielectric layer in the grating groove as a highly efficient polarizing beam splitter (PBS), to reflect s-polarized light and transmit p-polarized light in a wide spectrum band. This novel structure is designed at a wavelength of 1550 nm to be used in the optical communication wavelength band. High polarization efficiency and extinction ratio for both reflected and transmitted light are obtained by optimization of the designed structure. Moreover, it is shown that this structure can exhibit extremely high extinction ratio in the optical communication band with less dependence on the grating parameters and on the incidence angle, which greatly ease the fabrication of such kind of gratings.     

亚波长金属偏振分束光栅设计分析

结合有效介质理论和薄膜光学的抗反射设计方法,设计了基于0.65μm工作波长的亚波长金属偏振分束光栅,给出了光栅的优化设计参数,采用严格耦合波理论分析了光栅的偏振分束特性.结果表明,亚波长金属光栅对TE偏振表现为金属膜特性,具有高反射,对TM偏振表现为介质膜特性,具有高透射,在-30°<θ<30°的大入射角范围和0.47μm<λ<0.80μm的宽入射波谱内,该光栅的透射光和反射光均具有高偏振消光比和低插入损耗的特点. 关键词： 亚波长金属偏振分束光栅 有效介质理论 薄膜光学 严格耦合波理论     

Design of terahertz wave polarizing beam splitter

In this paper, we design a THz wave polarizer based on a periodic symmetrical thin film structure, which operates over a broadband THz frequency region (1.0–2.0 THz) and over an effective wide range of incident THz wave (72–84°). The spectral performance of this structure is characterized by transfer matrix method calculations. Results of simulations show that the polarizer is highly transmittance for TE polarized THz wave as well as highly reflecting for TM polarized THz wave.     

Five-port beam splitter of a single-groove grating

A single-groove grating for five-port TE-polarization beam splitting under normal incidence at the wavelength of 1550 nm is presented. The transmitted diffraction efficiency of the gratings is over 94.5% with uniformity better than 2%. A physical view of diffraction inside the grating is presented by the simplified modal method(SMM).Initial parameters of the grating profiles are obtained by use of SMM and then optimized by employing rigorous coupled-wave analysis and the simulated annealing algorithm.     

亚波长介质偏振分束光栅的衍射特性

 采用严格耦合波理论并结合矩阵LU分解法,分析了亚波长介质光栅的刻槽深度、占空比、入射角、入射波长等参数对TE偏振和TM偏振0级衍射效率的影响。结果表明:在1 550 nm波长处,出现瑞利反常现象。由此提出利用瑞利反常现象设计工作波长为1 550 nm的偏振分束光栅,通过优化设计确定了最佳设计参数,即光栅周期为l0/2,瑞利入射角为30°,刻槽深为0.9l0,占空比为0.5。结果表明,参数优化后的偏振分束光栅可以使TE偏振0级反射波和TM偏振0级透射波同时达到近100%的衍射效率。     

Construct a polarizing beam splitter by an anisotropic metamaterial slab

We present a theoretical investigation of polarizing beam splitters based on an anisotropic metamaterial (AMM) slab. At the interface associated with a certain AMM, TE- and TM-polarized waves exhibit opposite amphoteric refraction characteristics, such that one polarized wave is positively refracted whereas the other is negatively refracted. The opposite amphoteric refractions result in a large birefringence in the AMM slab. By suitably using the large birefringence, we introduce a very simple and very efficient beam splitter to route the light. We show that the splitting angle and the splitting distance between TE- and TM-polarized beams is the function of anisotropic parameters, incident angle and slab thickness. PACS 41.20.Jb; 42.25.Gy; 78.20.Ci     

Broad band beam splitter based on the double-groove fused silica grating

In this paper, we propose a broad band 1 × 3 beam splitter operating in the telecommunication wavelength band under normal incidence, this device consisting of a double-groove fused silica grating layer is designed with using the inverse mathematical method and rigorous vector diffraction theory. It is shown from our calculations that the device presents excellent beam splitter ability for TE polarization light with the average diffraction efficiencies is more than 95% over ∼100 nm wavelength range, moreover, the uniformity of our beam splitter is better than 2% in the whole wavelength band. Furthermore, the physical understanding of the diffraction behaviors taking place inside the beam splitter gratings can be explained by the modal method.     

Polarizing beam splitter of a deep-etched fused-silica grating

We described a highly efficient polarizing beam splitter (PBS) of a deep-etched binary-phase fused-silica grating, where TE- and TM-polarized waves are mainly diffracted in the -1st and 0th orders, respectively. To achieve a high extinction ratio and diffraction efficiency, the grating depth and period are optimized by using rigorous coupled-wave analysis, which can be well explained based on the modal method with effective indices of the modes for TE/TM polarization. Holographic recording technology and inductively coupled plasma etching are employed to fabricate the fused-silica PBS grating. Experimental results of diffraction efficiencies approaching 80% for a TE-polarized wave in the -1st order and more than 85% for a TM-polarized wave in the 0th order were obtained at a wavelength of 1550 nm. Because of its compact structure and simple fabrication process, which is suitable for mass reproduction, a deep-etched fused-silica grating as a PBS should be a useful device for practical applications.     

Polarizing binary diffraction grating beam splitter

We report a polarizing beam splitter that uses binary phase gratings written onto a liquid-crystal spatial light modulator. These gratings produce several linearly polarized diffracted orders and a zeroth-order beam whose polarization state can be completely controlled. Experimental results are shown.     

Broadband polarizing beam splitter with an embedded metal-wire nanograting

An embedded metal-wire nanograting is designed and fabricated for the first time to our knowledge. This artificial material could be used as a broadband polarizing beam splitter to reflect s-polarized light and transmit p-polarized light. An upper-cladding layer of the same material as the gratings is deposited on the ridge of the gratings, whereas the metal wire is deposited in the grating trenches. This embedded structure makes the grating more firm in its applications. High polarization efficiency and low insertion loss with a broad wavelength range (900-1700 nm) and a wide angular tolerance are obtained by optimization of the designed structure.     

Polarization Sagnac interferometer with a reflective grating beam splitter

All-reflective interferometric gravitational-wave detector configurations with a diffraction grating as a power beam splitter have been proposed to reduce thermal lensing. We demonstrate the use of a diffraction grating as a polarization beam splitter in a zero-area polarization Sagnac interferometer.     

Polarization beam splitter using a binary blazed grating coupler

A novel polarization beam splitter using a two-layer grating coupler is proposed and demonstrated. It can directly couple the normally incident light from fiber into two separate waveguides according to their polarization states while splitting them. It realizes high coupling efficiency and a good extinction ratio by using binary blazed grating couplers. The coupling length is less than 14 microm. The extinction ratio is better than 20 dB for both polarizations over a 40 nm wavelength range, and the coupling efficiencies for the two layers are 58% and 50%.