Development Of Spatial Light Modulators Research Articles

Comparative electronic speckle pattern interferometry using adaptive holographic illumination

The development of spatial light modulators enables the application of active holographic optical elements in electronic speckle pattern interferometry. In our work adaptive comparative measurement is done, where an optically reconstructed image of a recorded or simulated single or double exposure hologram is used for holographic illumination of another object. In this paper, we present experimental results of measuring the difference of two deformations using this technique. The displacement difference can also be obtained numerically, if the wavefront used as a coherent illuminating mask does not belong to an existing object. This type of interferometer can easily adapt to the change of measuring conditions.

Electrical Control of Plasmon Resonance of Gold Nanoparticles Using Electrochemical Oxidation

A large shift of the localized surface plasmon resonance (LSPR) spectrum of gold nanoparticles was attained by electrochemical oxidation of the nanoparticle surface. This oxidation occurred in the cell, which consisted of a pair of indium tin oxide (ITO) electrodes and water medium between the electrodes. On one side of the ITO electrode, the gold nanoparticles were adsorbed. With the application of a voltage of 5 V to the cell, a spectrum shift as large as 68 nm was obtained. Though the spectrum shift has already been observed by changing liquid crystal (LC) orientation surrounding gold nanoparticles, the size of the shift was not large (11 nm). That was because the variation of the effective refractive index of LC was rather small. Our large shift due to electrochemical oxidation resulted from the large refractive index of Au−O. The electrochemical oxidation was confirmed by XPS analysis of the gold nanoparticles with the LSPR spectrum shift. Other possible mechanisms of the shift such as charge localization, aggregation, and adsorption of charged materials proved to have no effect via SEM measurement and so on. This large shift of the resonance spectrum can be expected to lead to further development of spatial light modulators for next-generation optical communications and displays.

Optical Switching of a Ferroelectric Liquid Crystal Spatial Light Modulator by Photoinduced Polarization Inversion

Surface-stabilized ferroelectric liquid crystals(FLCs) have enabled the development of spatial light modulators (SLMs) with fast response times, high viewing contrasts, and orientational bistability, which allow digital information to be stored in a FLC-SLM film. It is shown that optical switching of an FLC-SLM can be achieved intrinsically with a visible light source using the chiral thioindigo dopant shown in the Figure.

Development of spatial light modulators with nonlinear organic materials

An electrically addressable spatial light modulator is designed using nonlinear organic materials for optical information processing and display. One candidates for spatial light modulator (SLM) material is a nonlinear organic polymer of poly-methyl-methacrylate doped with disperse red 1. The measured electrooptic coefficient r33 is 2.9 pm/V at the wavelength of 633 nm. Resonator structure for a material is discussed with the goal of increasing electrooptic effects for SLM applications.

Operation of optical information retrieval system using spatial light modulator

AbstractOptical information retrieval systems based on Fourier optics and using holographic memories of high‐density recording capability, which raise the possibility of parallel information processing, have been proposed for a long time. However, the development of spatial light modulators which are the key devices in such systems has been delayed considerably and, so far, there is no report on optical information retrieval systems using spatial light modulators.With this as background, a spatial light modulator (SLM) based on a large‐permittivity crystal is fabricated and its operation in a small‐size system is verified. First, based on the function of the spatial modulator, the hologram and the detection sections are designed and specifications of the system are decided. Next, the two different schemes of synchronous and direct detection methods are applied to the information retrieval of 18 bits consisting of nine pieces of holograms. As a result, it is understood that retrieval is possible using even the currently available spatial light modulators. The relation between the functions of the SLM and the system also is clarified. However, there are several problems in realization of such systems, a discussion of which is presented in this paper.