Measuring the Mueller matrix of an arbitrary optical element with a universal SU(2) polarization gadget

AbstractThis paper focuses on the development of flat diffractive optical elements (DOEs) for protecting banknotes, documents, plastic cards, and securities against counterfeiting. A DOE is a flat diffractive element whose microrelief, when illuminated by white light, forms a visual image consisting of several symbols (digits or letters), which move across the optical element when tilted. The images formed by these elements are asymmetric with respect to the zero order. To form these images, the microrelief of a DOE must itself be asymmetric. The microrelief has a depth of ~ 0.3 microns and is shaped with an accuracy of ~ 10–15 nm using electron-beam lithography. The DOEs developed in this work are securely protected against counterfeiting and can be replicated hundreds of millions of times using standard equipment meant for the mass production of relief holograms.

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Enhancing the Optical Efficiency of Near-Eye Displays with Liquid Crystal Optics

Crystals ◽

10.3390/cryst11020107 ◽

2021 ◽

Vol 11 (2) ◽

pp. 107

Author(s):

Tao Zhan ◽

En-Lin Hsiang ◽

Kun Li ◽

Shin-Tson Wu

Keyword(s):

Virtual Reality ◽

Liquid Crystal ◽

High Efficiency ◽

Berry Phase ◽

Optical Element ◽

Liquid Crystal Polymer ◽

Proof Of Concept ◽

Optical Efficiency ◽

Crystal Polymer ◽

Light Efficiency

We demonstrate a light efficient virtual reality (VR) near-eye display (NED) design based on a directional display panel and a diffractive deflection film (DDF). The DDF was essentially a high-efficiency Pancharatnam-Berry phase optical element made of liquid crystal polymer. The essence of this design is directing most of the display light into the eyebox. The proposed method is applicable for both catadioptric and dioptric VR lenses. A proof-of-concept experiment was conducted with off-the-shelf optical parts, where the light efficiency was enhanced by more than 2 times.

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Experimental validation of depolarizing Mueller matrix model via ex vivo colon samples

Journal of Physics Conference Series ◽

10.1088/1742-6596/1859/1/012042 ◽

2021 ◽

Vol 1859 (1) ◽

pp. 012042

Author(s):

Deyan Ivanov ◽

Ekaterina Borisova ◽

Tatiana Novikova ◽

Razvigor Ossikovski

Keyword(s):

Matrix Model ◽

Experimental Validation ◽

Ex Vivo ◽

Mueller Matrix

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Holographic Display System to Suppress Speckle Noise Based on Beam Shaping

Photonics ◽

10.3390/photonics8060204 ◽

2021 ◽

Vol 8 (6) ◽

pp. 204

Author(s):

Di Wang ◽

Yi-Wei Zheng ◽

Nan-Nan Li ◽

Qiong-Hua Wang

Keyword(s):

Optical Element ◽

Speckle Noise ◽

Beam Shaping ◽

Diffractive Optical Element ◽

The Other ◽

Spatial Light Modulators ◽

Viewing Angle ◽

Display System ◽

Holographic Display ◽

Light Modulators

In this paper, a holographic system to suppress the speckle noise is proposed. Two spatial light modulators (SLMs) are used in the system, one of which is used for beam shaping, and the other is used for reproducing the image. By calculating the effective viewing angle of the reconstructed image, the effective hologram and the effective region of the SLM are calculated accordingly. Then, the size of the diffractive optical element (DOE) is calculated accordingly. The dynamic DOEs and effective hologram are loaded on the effective regions of the two SLMs, respectively, while the wasted areas of the two SLMs are performed with zero-padded operations. When the laser passes through the first SLM, the light can be modulated by the effective DOEs. When the modulated beam illuminates the second SLM which is loaded with the effective hologram, the image is reconstructed with better quality and lower speckle noise. Moreover, the calculation time of the hologram is reduced. Experiments indicate the validity of the proposed system.

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