Effect of polarization mode on interference processing by dual-injection four-beam laser

Abstract

The four-beam laser interference processing technology has obtained good theoretical and experimental progress in the preparation of drug-loaded microstructures of coronary stent, and further improving the effect of processing has become a hotspot in recent research. This paper analyzes and calculates the light intensity distribution under different polarization combinations of four-beam lasers. Through modeling and simulation, the interference processes and results under three different polarization modes were simulated, and the higher interference light intensity was obtained in TE-TE-TM-TM mode; based on this, a dual-injection four-beam interference lithography system was built, and interference processing experiments were performed on silicon wafer. The laser wavelength used is 1064 nm, the energy of the four lasers is 97 mJ, 80 mJ, 97 mJ, and 78 mJ, all four beams have an incident angle of 45 degrees, the azimuth angles are 0 degrees, 90 degrees, 180° and 270°, the pulse width is 8.2 ns, the repetition frequency is 10 Hz, and the exposure time is 60 s. In the experiment, the microarray structure of the hole array with a period of 1.073 μm was obtained, which is in line with the simulation results. The work in this paper shows that when the combined polarization mode is TE-TE-TM-TM, the dual-injection four-beam interference processing system can achieve the best processing effect.