Research On Key Technologies Of Holographic Femtosecond Laser Parallel Processing

Femtosecond laser processing technology is cutting-edge technology in the field of nanofabrication, which has many advantages such as real three-dimensional fabrication ability, high resolution, tiny heat affect and widespread application for verities materials. Traditional single-point processing has matured, but the low processing efficiency led to a micro-structure fabrication is too time-consuming and has become the main obstacle to its industrialization process. Therefore, improve the processing efficiency by parallel methods has important research value and significance. As the spatial light modulator (SLM) technology development, the use of the SLM loading computer-generated hologram (CGH) to achieve parallel processing design, not only eliminates the cost of the diffractive optical element prepared in the original parallel processing, but also meets arbitrary structure preparation requirements due to the multifocal array of flexible controllability.Therefore, femtosecond laser holographic parallel processing based on SLM has aroused wide concern. It provides an important direction to improve the efficiency of femtosecond laser processing and creates an effective way for the mass production of three-dimensional functional devices. However, as a new research topic, there are many problems. this paper gives the relevant research work.This article comes from the natural science key project of Anhui province (KJ2011A014) and the main contents are as follow:Based on the study of femtosecond laser holographic parallel processing development and major domestic and foreign research status, this paper build a femtosecond laser holographic parallel processing system, and develop a set of integrated program including point-to-point scan recording, auto focusing and reading.Some issues of femtosecond laser holographic parallel processing is present. Firstly, analysis of the existing optical system parameter and discussion of its drawbacks, then a rational design hologram is put forward to improve the uniformity under the restricted condition. Secondly, the zero-order beam suppression, analysis of zero-order diffracted beam interference on the reconstruction quality, demonstration of hologram optimization loading blazed grating and phase information of divergent spherical wave not only to achieve elimination of the zero-order beam, but also improve the diffraction efficiency. Thirdly, refractive index mismatch problem, using the intensity of point spread function (IPSF) to calculate the focal intensity distribution and theoretical research on refractive index mismatch. This paper through hologram generated diffractive optical elements to optimize and compensate shift and distort the focal point caused by aberration function.These issues are very significant in the field of micro-nanofabrication and optical storage and all these efforts laid a good foundation for our projects and improvements in the research area.