Research Of Amplitude Spatial Light Modulator And Beam Manipulation Characteristics

In recent years, with the rapid development of the microelectronics and photonics technologyand their close combination, emergence of various spatial light modulators has been greatlypromoted. The spatial light modulator has an important function of modulating beam in real time,which makes it act as an important controlling component. It has an wide application prospectsinimplementing real-time optical information processing and so on.This thesis is mainly divided into two parts. Part one is based on studying some relevantcharacteristics of spatial light modulator in detail, then designing and manufacturing spatial lightmodulator, finally constructing the experimental platform and making experiments. Part two mainlystudies a variety of special vector beam focusing characteristics under different beam parameters.The followings are the major aspects of this research work.1. Some basic theory of the liquid crystal spatial light modulator was presented. First of all, weintroduce the relevant characteristics of the liquid crystal material briefly and the development ofthe spatial light modulator. Then we study the modulating theory about the twisted nematic typespatial light modulator and finally we study the complex amplitude modulation theory of the liquidcrystal spatial light modulator. These research contents lay the theoretical groundwork for theproduce of the subsequent hardware circuit board.2. Designing and making a hardware circuit of the spatial light modulator. Using the moduledesign concept to divide the hardware circuit into seven modules, including the LCD displaymodule, the single-chip circuit module, the signal processing module, the sample/hold module, theclock signal generation module, the PLL module and power supply module. Meanwhile, we alsodesign and debug the PCB board, and we display the PCB actural picture.3. Doing the experiment through designing and constructing the experimental platform.Liquid crystal spatial light modulator can display computer-generated hologram in real time, whichcan reproduce any object described by number. Therefore, liquid crystal spatial light modulator canact as an important regulator device to apply in the practical optical path. The experiment producesthe star-shaped controllable beam based on the computer-generated hologram, and the experimentalso verifies that the spatial light modulator could meet experimental requirements.4. Based on the vector diffraction theory, we studied a variety of special vector beam focusingproperty under different beam parameters. Mainly including:1).focus shaping of Bessel-Gaussbeam with radial varying polarization.2). Focusing patterns of linearly polarized Lorentz-Gaussianbeam with one optical vortex.3).Focal patterns of sine-azimuthal wavefront-modulated cosh-Gaussian beams by half space phase plate.4).Optical gradient force of cosh-Gaussian withsine-azimuthal and half-space phase modulation.5).Sine-azimuthal wavefront-modulatedcosh-Gaussian beams with half-space amplitude modulation.6).Sharper focus disappear for radiallypolarized beam in highly focusing system. For these particular vector beams, when the beamparameters are changed, light intensity distribution patterns will change.