Engineering Of Complex Optical Fields And Its Applications

Generation of optical fields with complex spatial distribution in the cross section is of great interest in application areas where exotic optical fields are desired, including particle manipulation, optical nanofabrication, beam shaping and optical imaging. The dissertation is organized in two parts. In the first part, different aspects of the optical field are controlled with different approaches used in four projects. First, a diffractive optics element (DOE) Simulator consisting of 4-f imaging systems and reflective spatial light modulator (SLM) is introduced, where the phase is modulated. In the second project, a complex optical filter design using optical antennas is presented for optical needle field generation, using the amplitude and binary phase modulation. In the third example, a "Bull's Eye" structure on fiber end is analyzed and demonstrated as a polarization sensitive device for cylindrical vector beam generation, where the SOP can be controlled. As the last demonstration, the vectorial beam is constructed by superimposing x-polarized Gaussian and y-polarized Laguerre Gaussian is introduced as one type of second order full Poincare beams, which can be realized using liquid crystal (LC) based device. The demands to arbitrarily tailor the properties of optical fields lead to our Vector Optical Field Generator (VOF-Gen). In the second part, a vectorial optical field generator capable of creating arbitrarily complex beam cross section is designed, built and tested. Based on two reflective phase-only liquid crystal spatial light modulators, this generator is capable of controlling all the parameters of the spatial distributions of an optical field, including the phase, amplitude and polarization (ellipticity and orientation) on a pixel-by-pixel basis. Various optical fields containing phase, amplitude and/or polarization modulations are successfully generated and tested using Stokes parameter measurement to demonstrate the its capability and versatility.