optical patterns controlled by computerized spatial light modulator

In this work, a contemporary optical system is designed using a technology of spatial light modulator (SLM). This system is depending on the ability of altering light beam into different optical patterns according to a signal feedback injected computationally to the SLM. The effects of control parameters on the SLM operation are studied such us brightness (B) which determines the constant DC voltage applied to SLM pixels, and contrast (C) determines the maximum AC voltage amount that can be applied to the SLM. The influences of the transmission linearity of image intensity are controlled by the gamma adjustment which can be used to align non linearity of image intensity. The grey scale is used to control and imagine which signals corresponding to grey levels and image location. The resolution and orientation of the obtained images are altered by the screen format to make optical experiments more satisfied, hence different ratios of amplitude and phase modulation can be understood.

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Study on Aided Optical Alignment by Programmable Spots Array Generated by Off-Axis Parabolic Phase Based on LCoS-SLM

Applied Sciences ◽

10.3390/app10238382 ◽

2020 ◽

Vol 10 (23) ◽

pp. 8382

Author(s):

Zhen Zeng ◽

Zexiao Li ◽

Fengzhou Fang ◽

Xiaodong Zhang

Keyword(s):

Liquid Crystal ◽

Optical System ◽

Phase Modulation ◽

Spatial Light Modulator ◽

Incident Light ◽

Alignment Method ◽

Light Modulator ◽

Optical Alignment ◽

Liquid Crystal On Silicon

We present an aided optical alignment method using the liquid crystal on silicon spatial light modulator (LCoS-SLM). An optical system composed of an interferometer and an LCoS-SLM was established to verify the effectiveness of the method. The system was also calibrated to solve the phase modulation nonlinear and nonuniformity problem for better performance of LCoS-SLM as an easily programmable phase compensator. The LCoS-SLM could modulate the phase of incident light precisely to generate an accurate phase desired to achieve a virtual off-axis parabolic phase to generate light spots array. Finally, the 2 × 2 light spots array generated by the optical system was used to verify its potential in optical alignment.

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Characterization of Spatial Light Modulator Based on the Phase in Fourier Domain of the Hologram and Its Applications in Coherent Imaging

Applied Sciences ◽

10.3390/app8071146 ◽

2018 ◽

Vol 8 (7) ◽

pp. 1146 ◽

Cited By ~ 3

Author(s):

Huaying Wang ◽

Zhao Dong ◽

Feng Fan ◽

Yunpeng Feng ◽

Yuli Lou ◽

...

Keyword(s):

Phase Modulation ◽

Spatial Light Modulator ◽

Light Modulator ◽

Coherent Imaging ◽

Grey Scale ◽

Optical Distance ◽

Incident Plane ◽

Fourier Spectra ◽

Plane Light

Although digital holography is used widely at present, the information contained in the digital hologram is still underutilized. For example, the phase values of the Fourier spectra of the hologram are seldom used directly. In this paper, we take full advantage of them for characterizing the phase modulation of a spatial light modulator (SLM). Incident plane light beam is divided into two beams, one of which passes the SLM and interferes with the other one. If an image with a single grey scale loads on the SLM, theoretical analysis proves that the phase of the Fourier spectra of the obtained hologram contains the added phase and a constant part relative to the optical distance. By subtracting the phase for the image with the grey scale of 0 from that for the image with other grey scales, the phase modulation can be characterized. Simulative and experimental results validate that the method is effective. The SLM after characterization is successfully used for coherent imaging, which reconfirms that this method is exact in practice. When compared to the traditional method, the new method is much faster and more convenient.

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Phase Compensation of the Non-Uniformity of the Liquid Crystal on Silicon Spatial Light Modulator at Pixel Level

Sensors ◽

10.3390/s21030967 ◽

2021 ◽

Vol 21 (3) ◽

pp. 967

Author(s):

Zhen Zeng ◽

Zexiao Li ◽

Fengzhou Fang ◽

Xiaodong Zhang

Keyword(s):

Liquid Crystal ◽

Phase Modulation ◽

Spatial Light Modulator ◽

Characteristic Curve ◽

Physical Structure ◽

Measuring System ◽

Light Modulator ◽

Phase Compensation ◽

Modulation Characteristic ◽

Liquid Crystal On Silicon

Phase compensation is a critical step for the optical measuring system using spatial light modulator (SLM). The wavefront distortion from SLM is mainly caused by the phase modulation non-linearity and non-uniformity of SLM’s physical structure and environmental conditions. A phase modulation characteristic calibration and compensation method for liquid crystal on silicon spatial light modulator (LCoS-SLM) with a Twyman-Green interferometer is illustrated in this study. A method using two sequences of phase maps is proposed to calibrate the non-uniformity character over the whole aperture of LCoS-SLM at pixel level. A phase compensation matrix is calculated to correct the actual phase modulation of the LCoS-SLM and ensure that the designed wavefront could be achieved. Compared with previously known compensation methods, the proposed method could obtain the phase modulation characteristic curve of each pixel on the LCoS-SLM, rather than a mono look-up table (LUT) curve or multi-LUT curves corresponding to an array of blocks over the whole aperture of the LCoS-SLM. The experiment results show that the phase compensation precision could reach a peak-valley value of 0.061λ in wavefront and this method can be applied in generating freeform wave front for precise optical performance.

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Measurement of phase modulation characteristics of liquid crystal spatial light modulator

10.1117/12.676511 ◽

2006 ◽

Cited By ~ 1

Author(s):

Hongxin Zhang ◽

Jian Zhang ◽

Liying Wu ◽

Yan Zhang

Keyword(s):

Liquid Crystal ◽

Phase Modulation ◽

Spatial Light Modulator ◽

Light Modulator

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Optical attenuator based on phase modulation of a spatial light modulator

Chinese Optics Letters ◽

10.3788/col201513.082301 ◽

2015 ◽

Vol 13 (8) ◽

pp. 082301-82304 ◽

Cited By ~ 1

Author(s):

Chao Liu Chao Liu ◽

Di Wang Di Wang ◽

Lixiao Yao Lixiao Yao ◽

Lei Li Lei Li ◽

Qionghua Wang Qionghua Wang

Keyword(s):

Phase Modulation ◽

Spatial Light Modulator ◽

Light Modulator

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Pseudo-Color Coded Optical System Based on the Spatial Light Modulator and Charge-Coupled Device

Volume 10: Emerging Technologies and Topics; Public Policy ◽

10.1115/imece2012-86642 ◽

2012 ◽

Author(s):

S. N. Zhao ◽

H. Chang ◽

J. Wei ◽

Z. Wei

Keyword(s):

Real Time ◽

Optical System ◽

Spatial Light Modulator ◽

Processing System ◽

Optical Processing ◽

Gray Scale ◽

Light Modulator ◽

Time Modulation ◽

Gray Scale Image ◽

Pseudo Color

A new pseudo-color coded optical system based on the liquid crystal spatial light modulator (LC-SLM) and a digital camera (CCD) is proposed. The SLM is used to replace the holographic grating with gray-scale image information, a gray-scale image in real-time modulation methods is proposed by synthesizing phase hologram and Ronchi grating, combined with the 4f coherent optical processing system and spatial filtering. For the high resolution gray image processed with existing digital pseudo-color method, the color sensitivity is low, algorithm is very complex. For traditional optical pseudo-color method, the gray scale image needs chemical pretreatment. The process is complex and time-consuming, and the real-time modulation could not be achieved. Our new method has enhanced the flexibility and adaptability of the optical pseudo-color, and give full play to the high sensitivity, high-capacity, rich colors and other features of the optical processing mode. At the same time, it overcomes the disadvantages of pure optical system which could not perform real-time processing. Therefore, it can be widely used in the field of remote sensing, biomedical, environmental monitoring, public security and criminal investigation, etc.

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