Super resolution imaging achieved by using on-axis interferometry based on a Spatial Light Modulator

Hussain, Anwar; Martínez, José Luis; Lizana, Ángel; Campos, Juan

doi:10.1364/oe.21.009615

Cited by 25 publications

(20 citation statements)

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“…4 constitute a generalization of the study given in Ref. [13], where the simultaneous illumination based technique was applied to the one-dimensional case. In this section, the super-resolved method is extended to the two dimensional case, leading to significant improvement in the image resolution.…”

Section: Simulation Resultsmentioning

confidence: 98%

“…We have presented some additional results for a recently proposed method [13] to achieve superresolution in an optical imaging system. In particular, we have used a 4f optical system to better show the behavior of the method.…”

Section: Resultsmentioning

confidence: 99%

“…The shifting process, necessary to retrieve the correct values for the coefficients , is detailed in Ref. [13]. By obtaining accurate values for the coefficients, the following synthetized spectrum is obtained: (7) Equation (7) gives the synthesized spectrum, having higher spatial frequencies than the limited object spectrum.…”

Section: Mathematical Modelmentioning

confidence: 99%

“…Recently, we have proposed a new superresolution technique based on a spatial light modulator [13]. In the proposed technique, the object is illuminated from different defined directions and several interferograms are obtained by their mutual interference.…”

Section: Introductionmentioning

confidence: 99%

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Multiplexing structured illumination in spatial light modulators to achieve superresolution

Hussain¹

2013

Opt. Pura Apl.

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ABSTRACT:We present some numerical results corresponding to a recently proposed structured illumination based set-up able to achieve resolution beyond the diffraction limit in 4f optical setup. The technique is based on the use of a liquid crystal display to multiplex the different linear phases which produce all the tilted plane waves at the same time. At the SLM plane constant phases are assigned to each tilted beam. The object is illuminated several times with simultaneous illumination (i.e., simultaneous tilted beams), every time carrying different constant phases. A total of interferograms are recorded at the CCD plane, corresponding to the same number of constant phases sets. The proper selection of phases helps to separate the correlated terms. In a post processing procedure, each hologram is transformed to the spectrum domain and spatially shifted to its proper position. The combination of these shifted segments of the object spectrum gives the synthesized spectrum. To obtain super resolved image inverse Fourier transform is taken of the synthesized spectrum.Key words: Spatial Light Modulators, Super-Resolution, Multiplexed Illumination. RESUMEN:En este trabajo se presentan resultados numéricos correspondientes a un nuevo método para la obtención de imágenes super-resueltas que se basa en la iluminación estructurada del objeto a estudiar. En particular, la iluminación estructurada consiste en diferentes ondas planas con distintas inclinaciones que iluminan el objeto simultáneamente. Para generar dicha iluminación, se utiliza una pantalla de cristal líquido donde se multiplexan diferentes fases lineales, que originan las distintas ondas planas simultáneamente. Para recuperar apropiadamente la información extra de las frecuencias altas del objeto, que está codificada en los diferentes haces inclinados, se ilumina el objeto diversas veces con la iluminación estructurada, pero añadiendo diferentes fases constantes a los distintos haces. Los correspondientes interferogramas se capturan mediante el uso de una cámara CCD. La selección adecuada de los valores para las fases constantes añadidas, permite separar los diferentes términos correlacionados. Finalmente, en un post-procesado, se realiza la Transformada de Fourier de cada holograma obtenido, y se desplaza cada fragmento del dominio de frecuencias del objeto a su posición correcta. Aplicando la transformada de Fourier inversa al espectro sintetizado, obtenemos una imagen super-resuelta del objeto.Palabras clave: Modulador Espacial de Luz, Super-Resolución, Iluminación Multiplexada.

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Section: Simulation Resultsmentioning

confidence: 98%

Section: Resultsmentioning

confidence: 99%

Section: Mathematical Modelmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Multiplexing structured illumination in spatial light modulators to achieve superresolution

Hussain¹

2013

Opt. Pura Apl.

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“…Unlike amplitude-modulating LCOS devices (mainly for video and image projections), phase-only modulating LCOS devices have a wide range of applications based on the spatial modulation of coherent lights, [14][15][16] including real-time holography, 17 optical correlators, 18 wavelength selective switches, 19,20 reconfigurable optical add-drop multiplexers [20][21][22] and diffractive optical components. [23][24][25] The first attempt to drive an LC pixel array from a single crystal silicon active backplane was proposed by Ernstoff et al 26 in the early 1970s.…”

Section: Brief Introduction To Lcos Devicesmentioning

confidence: 99%

Fundamentals of phase-only liquid crystal on silicon (LCOS) devices

2014

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This paper describes the fundamentals of phase-only liquid crystal on silicon (LCOS) technology, which have not been previously discussed in detail. This technology is widely utilized in high efficiency applications for real-time holography and diffractive optics. The paper begins with a brief introduction on the developmental trajectory of phase-only LCOS technology, followed by the correct selection of liquid crystal (LC) materials and corresponding electro-optic effects in such devices. Attention is focused on the essential requirements of the physical aspects of the LC layer as well as the indispensable parameters for the response time of the device. Furthermore, the basic functionalities embedded in the complementary metal oxide semiconductor (CMOS) silicon backplane for phase-only LCOS devices are illustrated, including two typical addressing schemes. Finally, the application of phase-only LCOS devices in real-time holography will be introduced in association with the use of cutting-edge computer-generated holograms. The architecture of LCOS devices is similar to conventional LC devices except that a silicon backplane constitutes one of the substrates (Figure 1). The silicon CMOS backplane consists of the electronic circuitry that is buried underneath pixel arrays to provide a high 'fill factor'. The pixels are aluminum mirrors deposited on the surface of the silicon backplane. The incident light is transmitted through the LC layer with almost zero absorption. The integration of high-performance driving circuitry allows the applied voltage to be changed on each pixel, thereby controlling the phase retardation of the incident wavefront across the device. Currently, there are two types of light modulation using LCOS devices, amplitude modulation and phase modulation. In the former case, the amplitude of the light signal is modulated 6,7 by varying the linear polarzation direction of the incident light passing through a linear polarizer, the same principle used in a standard LC television. In the latter case, the phase delay is accomplished by electrically adjusting the optical refractive index along the light path, which is possible because of the non-zero birefringence of the LC materials in use but should be carefully characterized. [8][9][10][11][12][13] In a phase-only LCOS SLM modulator, no light absorption by polarizers or other light-absorbing components will occur, such that the maximum light efficiency can be expected.Currently, most of the conventional LC devices are not able to efficiently modulate the phase of an incident wavefront. For instance, the LC device structure using thin film transistors is not suitable for phase modulation because an appropriate electro-optic effect has not been used (see the section on 'Twisted nematic (TN) configuration' and the section on 'VAN configuration' for details). Moreover, the pixels of this type of device are too large to provide acceptably large diffraction angles. In addition, the pixel circuitry and connection tracks are in the light path such that the ...

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