scholarly journals Digital analysis of a speckle pattern of chaotic mode composition and restoration of a regular intensity pattern after a multimode fiber

2021 ◽  
Vol 45 (2) ◽  
pp. 179-189
Author(s):  
A.V. Volyar ◽  
M.V. Bretsko ◽  
Y.E. Akimova ◽  
Y.A. Egorov
Keyword(s):  
Spatial Light Modulator ◽  
Speckle Pattern ◽  
Reference Beam ◽  
Random Phase ◽  
Mode Matching ◽  
Digital Analysis ◽  
Light Modulator ◽  
Intensity Pattern ◽  
Mode Composition ◽  
Chaotic Mode

A process of mode matching in a chaotic speckle pattern without a reference beam responsible for the formation of a holographic grating was studied experimentally and theoretically. Our approach was based on measuring the amplitudes and phases of the Hermite-Gauss (HG) and Laguerre-Gauss (LG) modes in a speckle pattern formed by the radiation of a multimode gradient fiber. The speckle pattern was formed in a hologram of a spatial light modulator using a multimode gradient fiber model while taking into account the mode and polarization dispersion, as well as random phase jumps of each eigenmode. We managed to match 210 modes of the speckle pattern and restore not only the original pattern, but also each structured LG mode and the entire chain of HG eigenmodes.

scholarly journals Compression of computer-generated holograms in image projection

2017 ◽  
Vol 9 (2) ◽  
pp. 60 ◽  
Author(s):  
Paula Adrianna Kochańska ◽  
Michal Makowski
Keyword(s):  
Spatial Light Modulator ◽  
Graphics Processing Unit ◽  
Random Phase ◽  
Speckle Noise ◽  
Processing Unit ◽  
Light Modulator ◽  
Computer Generated Holography ◽  
Image Projection ◽  
Bit Planes ◽  
Graphics Processing

Computer-generated holography is a technique of a lossless and lens-less forming of images. Methods that use local devices to compute such holograms are very power- and time-consuming. In order to make it possible to transfer the calculations to the cloud, it is necessary to elaborate efficient algorithms of a lossless compression. In this paper two methods of compression are presented and supported by both simulation and experimental results. A lossy compression method omitting certain bit-planes of the holographic data is also presented, which allows insignificant loss of information, while achieving a greater compression ratio. Full Text: PDF ReferencesM. Makowski "Simple holographic projection in color.", Opt. Express 20, 25130-25136 (2012). CrossRef M. Makowski, I. Ducin, K. Kakarenko, J. Suszek, A. Kowalczyk, "Performance of the 4k phase-only spatial light modulator in image projection by computer-generated holography, " Phot. Lett. Poland 8, 26-28 (2016). CrossRef A. Kowalczyk, M. Bieda, M. Makowski, I. Ducin, K. Kakarenko, J. Suszek, A. Sobczyk, "Analysis of computational complexity in holographic lens-less projection," Phot. Lett. Poland 6, 84-86 (2014). CrossRef M. Makowski, "Minimized speckle noise in lens-less holographic projection by pixel separation," Opt. Express 21, 29205-29216 (2013). CrossRef H. Niwase, N. Takada, H. Araki, Y. Maeda, M. Fujiwara, H. Nakayama, T. Kakue, T. Shimobaba, T. Ito "Real-time electroholography using a multiple-graphics processing unit cluster system with a single spatial light modulator and the InfiniBand network." Opt. Eng. 55, 093108-093108 (2016). CrossRef T. Shimobaba and T. Ito, "Random phase-free computer-generated hologram", Opt. Express 23(7) 9549-9554 (2015) CrossRef S.R. Kodituwakku, "Comparison of lossless data compression algorithms for text data", Indian Journal of Computer Science and Engineering Vol 1 No 4 416-426 (2010) DirectLink

Measurement of the adjustable slight roughness emulated by a spatial light modulator employing the vortex beam speckle pattern

2020 ◽  
Vol 59 (12) ◽  
pp. 3630
Author(s):  
Can Cui ◽  
Zhi Wang ◽  
Xiangkong Zhan ◽  
Jian Wang ◽  
Lanlan Liu ◽  
...  
Keyword(s):  
Spatial Light Modulator ◽  
Speckle Pattern ◽  
Vortex Beam ◽  
Light Modulator

Radial shearing speckle pattern interference system based on spatial light modulator

2021 ◽  
Author(s):  
Shuangle Wu ◽  
Chen Li ◽  
Haotian Xie ◽  
Yanfeng Yao ◽  
Yonghong Wang
Keyword(s):  
Spatial Light Modulator ◽  
Speckle Pattern ◽  
Light Modulator ◽  
Interference System

scholarly journals Generation of Perfect Optical Vortices by Using a Transmission Liquid Crystal Spatial Light Modulator

2017 ◽  
Vol 2017 ◽  
pp. 1-10 ◽  
Author(s):  
Nelson Anaya Carvajal ◽  
Cristian H. Acevedo ◽  
Yezid Torres Moreno
Keyword(s):  
Liquid Crystal ◽  
Topological Charge ◽  
Spatial Light Modulator ◽  
Propagation Distance ◽  
Optical Vortex ◽  
Optical Vortices ◽  
Light Modulator ◽  
Intensity Pattern ◽  
Fourier Plane ◽  
Spiral Phase

We have experimentally created perfect optical vortices by the Fourier transformation of holographic masks with combination of axicons and spiral functions, which are displayed on a transmission liquid crystal spatial light modulator. We showed theoretically that the size of the annular vortex in the Fourier plane is independent of the spiral phase topological charge but it is dependent on the axicon. We also studied numerically and experimentally the free space diffraction of a perfect optical vortex after the Fourier back plane and we found that the size of the intensity pattern of a perfect optical vortex depends on the topological charge and the propagation distance.

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