Fabrication and performance evaluation of pixelated nano-wire grid polarizer

Author(s):  
Shengkui Gao ◽  
Raphael Njuguna ◽  
Viktor Gruev
Photonics ◽  
2018 ◽  
Vol 6 (1) ◽  
pp. 1 ◽  
Author(s):  
Luigi Consolino ◽  
Annamaria Campa ◽  
Davide Mazzotti ◽  
Miriam Vitiello ◽  
Paolo De Natale ◽  
...  

We report on the development, testing, and performance analysis of a bow-tie resonant cavity for terahertz (THz) radiation, injected with a continuous-wave 2.55 THz quantum cascade laser. The bow-tie cavity employs a wire-grid polarizer as input/output coupler and a pair of copper spherical mirrors coated with an unprotected 500 nm thick gold layer. The improvements with respect to previous setups have led to a measured finesse value F = 123, and a quality factor Q = 5.1·105. The resonator performances and the relevant parameters are theoretically predicted and discussed, and a comparison among simulated and experimental spectra is given.


Author(s):  
Liling Cho ◽  
David L. Wetzel

Polarized infrared microscopy has been used for forensic purposes to differentiate among polymer fibers. Dichroism can be used to compare and discriminate between different polyester fibers, including those composed of polyethylene terephthalate that are frequently encountered during criminal casework. In the fiber manufacturering process, fibers are drawn to develop molecular orientation and crystallinity. Macromolecular chains are oriented with respect to the long axis of the fiber. It is desirable to determine the relationship between the molecular orientation and stretching properties. This is particularly useful on a single fiber basis. Polarized spectroscopic differences observed from a single fiber are proposed to reveal the extent of molecular orientation within that single fiber. In the work presented, we compared the dichroic ratio between unstretched and stretched polyester fibers, and the transition point between the two forms of the same fiber. These techniques were applied to different polyester fibers. A fiber stretching device was fabricated for use on the instrument (IRμs, Spectra-Tech) stage. Tension was applied with a micrometer screw until a “neck” was produced in the stretched fiber. Spectra were obtained from an area of 24×48 μm. A wire-grid polarizer was used between the source and the sample.


2018 ◽  
Vol 30 (4) ◽  
pp. 267-291
Author(s):  
Mukesh Kumar ◽  
Avinash Moharana ◽  
Raj K. Singh ◽  
Arun K. Nayak ◽  
Jyeshtharaj B. Joshi

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