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1

Spatial light modulator design and generation of structured electromagnetic waves using digital light processors

Yalcinkaya F., Koc T., Pala Z.

Optica Applicata

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2022

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Vol. 52, nr 3

461--479

EN

Spatial light modulators (SLMs) are versatile devices used for optical studies. These instruments have a wide area of application in photonics. Additionally, SLMs have potential utility in different applications, such as biomedical applications, laser based surgery for precise cutting and as optical tweezers to separate cells in a petri container. However, the high cost of SLM devices prevents their widespread use in many areas, including industrial areas and scientific research laboratories. This paper demonstrates how to design a digital light processor (DLP) based low-cost SLM and describes how to obtain structured electromagnetic waves with the designed SLM. Therefore, this research was undertaken to design and produce a low-cost SLM device for optical applications. For this purpose, two prerequisites had to be fulfilled, the first was to use suitable components of a projection device with DLP-based digital micro-mirror device (DMD), and the second was to eliminate unnecessary SLM components from the system. Finally, holographic images reflected on the SLM screen were created by using Mathematica software program to change the amplitude and phase of the electromagnetic waves in order to obtain the structured electromagnetic waves.

2

Physical and mathematical model of the digital coherent optical spectrum analyser

Kolobrodov V. G., Tymchyk G. S., Mykytenko V. I., Kolobrodov M. S.

Optica Applicata

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2017

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Vol. 47, nr 2

273--282

EN

A physical and mathematical model of digital coherent optical spectrum analyzers is discussed. In digital coherent optical spectrum analyzers the input signal is forming as a two-dimensional transparency by means of a spatial light modulator. After Fourier transformation with a lens, multiplication by a spatial filter and second Fourier transformation, the signal is captured by a matrix detector for further computer processing. A lot of digital coherent optical spectrum analyzers and their components (laser, lighting system, spatial light modulator, Fourier lens and matrix detector) models were developed to calculate the signal at the matrix detector output. They use the impulse response and transfer function to evaluate the effectiveness of digital coherent optical spectrum analyzers. The analysis of mathematical relationships shows that the use of a discrete spatial light modulator for the signal input and a matrix detector for light field registration in the spectral domain when combined with computer technology greatly extends the functionality of digital coherent optical spectrum analyzer. The formulas for impulse response and transfer function calculations were obtained, which allows to analyze and optimize the digital coherent optical spectrum analyzer basic characteristics.

3

Fractal-like diffractive arrangement with multiple focal points

Mihailescu M., Preda A. M., Sobetkii A., Petcu A. C.

Opto-Electronics Review

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2009

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Vol. 17, No. 4

330-337

EN

In this paper we introduce a diffractive structure with a geometry which contains multiple Fresnel zone plates (MFZP) disposed in an arrangement based on a fractal-like rule. The corresponding diffracted intensity in planes perpendicular to the propagation axe presents two or more focal points. Their position and magnitude depend on geometrical parameters of the MFZP and on dimensions in the fractal-like arrangement. In our simulations we also analyze the influence in diffraction pattern of different non-binary phase levels in the MFZP plane. The MFZP structures with different values of geometrical and phase parameters are addressed to an optoelectronic device liquid crystal spatial light modulator (LCSLM), the experimental and simulation results are in a good agreement. The MFZP geometry with better optical parameters in diffraction pattern is then made on glass using electron beam lithography technique.

4

Electronically switchable diffractive optical elements

Lester G., Strudwick A., Coulston S.

Opto-Electronics Review

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2004

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Vol. 12, No. 3

313-316

EN

Liquid crystal filled polymer structure (LiCFiPS) devices consist of a polymer structure, which performs the desired spatial phase modulation of the incident light, filled with liquid crystal to permit modulation of this optical function. Potentially fabrication of this type of device may be carried out at very low cost using established polymer hot rolling or embossing techniques. Devices incorporating complex polymer structures as the diffractive element will inevitably have liquid crystal aligned at varying orientations to the surface. Switchable gratings with the liquid crystal aligned in the plane of the grating but either parallel or perpendicular to the grating rulings have been investigated as the two extremes of alignment. Good quality optical switching has been achieved for parallel aligned devices, however devices with the liquid crystal aligned perpendicular to the grating lines tend to show defects and inhomogeneities. While such devices might not offer the ultimate versatility of matrix addressed SLM devices they do offer electronic control of diffractive optical devices at very low cost.

5

Reconstruction of digital hologram by means of liquid crystal on silicon (LCOS) spatial light modulator

Michałkiewicz A., Kujawińska M.

Elektronika : konstrukcje, technologie, zastosowania

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2004

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Vol. 45, nr 8-9

278-280

EN

One of the methods to obtain 3D objects visualization is holography. The recent progress in CCD/CMOS cameras provides quick development of digital holographic recording. Optoelectronic reconstruction of digital holograms can be realized by means of variety of spatial light modulators, however each of them suffers several limitations due to big pixel size, Iow diffraction efficiency and noise. In the paper high efficiency liquid crystal on silicon (LCOS) spatial light modulator is proposed as the novel solution for optoelectronic holographic reconstruction. The experiments on reconstruction of various types of holograms by means of LCOS are demonstrated.

PL

Jedną z metod wizualizacji obiektów trójwymiarowych jest holografia. W ostatnich latach nastąpił postęp w technologii kamer CCD/CMOS, który umożliwił szybki rozwój holografii cyfrowej. Optoelektroniczna rekonstrukcja hologramów cyfrowych realizowana jest za pomocą szeregu przestrzennych modulatorów światła, jednakże większość z nich charakteryzują takie wady jak: zbyt duże wymiary piksela, niska wydajność dyfrakcyjna, powielanie obrazu oraz szumy. W artykule zaproponowano zastosowanie wysoko wydajnego ciekłokrystalicznego przestrzennego modulatora światła na krzemie do optoelektronicznej rekonstrukcji hologramów. Przedstawiono wyniki odtworzenia różnych typów hologramów w układzie z LCOS.