Beam alignment in Laser Interference Nanolithography

Laser Interference Nanolithography (LInL) can produce nanostructure patterns by two or more coherent laser beams on the sample surface. In LInL, incident positions, incident angles and space angles of beams determine the lithography pattern and exposure area. In this work, a method for beam alignment in LInL was described. The method is based on the detection of the light spot which is formed by the incident beam on the sample surface, obtaining the parameters of the light spot by image processing including the incident position, incident angle and space angle of the beam. Proper system alignment can eliminate errors of beam incidence to ensure that the final lithography pattern and the exposure area can comply with the design. Computer simulation and experimental results have shown the accuracy, repeatability and limitation of the method, and it can be used in laser interference nanolithography.