Determination of beam incidence conditions based on the analysis of laser interference patterns

Dapeng Wang, Zuobin Wang, Yong Yue, Juncai Yu, Chunlei Tan, Dayou Li, Renxi Qiu, Carsten Maple
2015 Optik (Stuttgart)  
Beam incidence conditions in the formation of two-, three-and four-beam laser interference patterns are presented and studied in this paper. In a laser interference lithography (LIL) process, it is of importance to determine and control beam incidence conditions based on the analysis of laser interference patterns for system calibration as any slight change of incident angles or intensities of beams will introduce significant variations of periods and contrasts of interference patterns. In this
more » ... work, interference patterns were captured by a He-Ne laser interference system under different incidence conditions, the pattern period measurement was achieved by crosscorrelation with, and the pattern contrast was calculated by image processing. Subsequently, the incident angles and intensities of beams were determined based on the analysis of spatial distributions of interfering beams. As a consequence, the relationship between the beam incidence conditions and interference patterns is revealed. The proposed method is useful for the calibration of LIL processes and for reverse engineering applications.
doi:10.1016/j.ijleo.2015.07.039 fatcat:hwh53nbeibcm3bhignqfssqcdm