Thin-film Polarizing Beam Splitter Research Articles

High-reliability infrared broadband thin-film polarizing beam splitter with ZnSe compensation layers.

Thin-film polarizing beam splitters (PBSs) fulfill a pivotal role in laser beam splitting, modulation, shaping and isolation. In this study, a high-reliability infrared broadband thin-film PBS was developed. To correct for tensile stress in Ge/YbF3 multilayer coatings, ZnSe compensation layers were incorporated in the multilayer design. The effects of different symmetrical periods on the spectral properties of the infrared PBS were systematically discussed. The infrared PBS operated at 45° and in the long-wave infrared (LWIR) band. Using the percent of optical extrema monitoring (POEM) strategy combined with the high-temperature optical constants (HTOC) of Ge film, the infrared PBS was precisely fabricated on ZnSe substrates. Subsequently, the spectral performance and film reliability of the infrared PBS were carefully characterized. Specifically, the transmittance of p-polarization surpassed 96%, while the extinction ratio exceeded 100:1 within the 10.6 ± 0.15 µm band. The infrared PBS demonstrated commendable environmental reliability, in addition to exhibiting excellent spectral characteristics.

TiO2/airgap-based polarizing beam splitter: design, simulation, and fabrication based on MEMS technologies

In this paper, we introduce a new thin-film polarizing beam splitter (PBS) based on air as a layer with a low refractive index (L) and titanium dioxide (TiO2) as a material with a high refractive index (H). A cube-type PBS presents an active area of approximately 1.0 × 1.0 mm2, and the airgap layer in conjunction with TiO2 thin-films provides an extremely high refractive index contrast (1.2). The PBS cube is projected onto a borosilicate glass substrate and the multiple layers obtained through TFCalcTM simulations, expressed in multiples of a quarter-wavelength optical thickness, are 1.6H L 1.1H 1.5L 1.1H L 1.6H. The projected structure ensures the separation of the polarizing states of light (transmission of the p-polarization and reflection of the s-polarization) from the visible to near infrared spectral range, over a bandwidth higher than 170 nm. This is the minimal working bandwidth obtained for visible range (centered at 550 nm), considering a polarization degree higher than 0.95. The projected PBS is fabricated based on conventional microelectromechanical systems (MEMS) technologies, namely, thin-film deposition, annealing, and etching processes. Finally, the fabricated PBS was experimentally characterized, with the measured transmittance of the fabricated structure reaching close to the expected TFCalcTM simulation result. This characterization is the final validation of the structure since, theoretically, reflection is the complement of transmission in a dielectric thin-film multilayer.

Achromatic Cycloidal Diffraction Gratings

A theory of a broadband thin-film polarizing beam splitter based on an anisotropic cycloidal diffraction grating is proposed. The achromatization of the grating is provided by creating two-layer chiral structures with an opposite twist sense. Such a system has almost 100% efficiency. The calculations were carried out by the Jones matrix method. The resulting efficiency and bandwidth are higher than the previously known results.

Analysis and verification of the nonlinear error resulting from the misalignment of a polarizing beam splitter in a heterodyne interferometer

In order to analyze and characterize the periodic nonlinear error resulting from the misalignment of a polarizing beam splitter (PBS) in a laser heterodyne interferometer more accurately, in this paper, starting from the light separating principle of thin-film PBS, we have found that the root cause of the periodic nonlinear error is the frequency mixing induced by the deviation from the Brewster angle of the incident angle or by the rotation of the incident plane when the PBS is misaligned. Moreover, we have established the direct function relationships between the periodic nonlinear error and different PBSs’ misalignment errors for the first time. The theoretical analysis shows that the periodic nonlinear error arising from the PBS’s yaw error is the largest and the maximal nonlinear errors are unequal even if the positive yaw angle is equal to the negative yaw angle. The nonlinear errors are much smaller under the PBS’s roll and pitch errors. The experiments of polarizing leakage and nonlinear error measurement under the PBS’s yaw error demonstrate that the experimental results are in agreement with the theoretical analysis.

Comparative Research on Different Solutions of a High-Performance Thin-Film Polarizing Beam Splitter

In the process of fabricating an ultra-high precision thin-film polarizing beam splitter (PBS), which is the key element in a new kind of Y-shaped cavity dual-frequency laser, low production yield is a serious problem. Based on the robust design method by controlling sensitivity of optical films to production errors, response characteristics to production errors of different kinds of PBSs are comparatively studied. By experimental study of robust design, essential determinant of sensitivity of PBSs to production errors is found to be the physical requirement that the propagation angle should be larger than the critical angle of total reflection of the interface between the substrate and outer space. By fulfilling the physical requirement, optimum incidence angle has been found by repeated robust design on different incidence angles, and a high-performance thin-film PBS with low sensitivity to production errors has been designed. The coating structure of the obtained PBS is simple and it is easy to be batch manufactured, which will make a positive impact on fabrication, engineering and application of the new Y-shaped cavity dual-frequency laser.

Design and fabrication of ultra-high precision thin-film polarizing beam splitter

An ultra-high precision thin-film polarizing beam splitter (PBS) has been designed and fabricated. Using Needle optimization technology, we design the thin-film polarizing beam splitter that is transparent for P polarization and reflective for S polarization with ultra-high precision at 64.8° angle of incidence and 632.8 ± 10 nm wavelength band. The experiments with the fabricated thin-film PBS demonstrate that both the reflectance of P polarization and transmittance of S polarization at 64.8° angle of incidence and 632.8 nm wavelength point are less than 0.02%, which is ultra-high for reported PBSs.

Nonpolarizing beam splitter designed by frustrated total internal reflection inside a glass cube: publisher’s note

It has come to the attention of the Optical Society of America that the article “Nonpolarizing beam splitter designed by frustrated total internal reflection inside a glass cube,” Xueke Xu, Jianda Shao, and Zhengxiu Fan, Appl. Opt.45, 4297–4302 (2006) should not have been submitted owing to its substantial replication, without appropriate attribution, of significant elements found in the previously published material: “High-performance thin-film polarizing beam splitter operating at angles greater than critical angle,” Li Li and J. A. Dobrowolski, Appl. Opt.39, 2754–2771 (2000); “The design of optical thin film coatings with total and frustrated internal reflection,” Li Li, Opt. Photon. News14(9), 24–30 (2003); and “Non-polarizing thin film interference filters with FTIR,” Li Li, Penghui Ma, and P. G. Verly, Optical Interference Coatings, OSA Technical Digest Series (Optical Society of America, 2004), paper ThD3.

High-performance thin-film polarizing beam splitter operating at angles greater than the critical angle

A new type of thin-film polarizing beam splitter (PBS) is proposed that is based on the effects of light interference and frustrated total internal reflection. This PBS has a significantly better performance than conventional thin-film PBS's. It is nonabsorbing, broadband, and wide angle and has high extinction ratios in both the transmitted and the reflected beams. The principles and theory of this PBS are described in detail. Several PBS's designed for the visible and the infrared spectral regions are described. The measured results for a prototype visible PBS of this type are presented as well.

Versatile frustrated-total-reflection polarizer for the infrared

A new type of thin-film polarizing beam splitter based on the frustrated-total-reflection effect is described. The device may be designed to transmit either p or s linearly polarized light. A polarization ratio on the order of 1000:1 is expected.