Abstract
The function of laser beam shaping is to manipulate the size, profile, irradiance and/or phase distribution of the laser beam for various applications, such as material processing, signal processing and illumination etc. For most applications, it is desired to transform the original Gaussian irradiance distribution into a flat-top uniform distribution, which is especially important for material processing and illumination. In this paper, two kinds of diffractive elements have been designed and analyzed, they can transform the original Gaussian irradiance distribution into a flat-top uniform distribution and can be applied them to material processing and illumination respectively. Firstly, a binary optical element with surface relief of four quantized levels associated with a cylindrical lens has been designed to transform the original Gaussian irradiance distribution into a line beam with flat-top uniform distribution and apply to laser annealing processing. Secondly, the diffraction pattern of coherent light source modulated by polymer lenslet array has been investigated, and applied to a laser illuminated projection system. The diffractive optical element, which can transfer the laser beam into a uniform illumination source on the microdisplay, has been designed and implemented with polymer thin film technology.