Preparation of new crystal 2-D optical low pass filter

Abstract

To restrain the high spatial frequency which is higher than the photoelectric image sensors sampling frequency, a two-dimensional crystal optical low pass filter (OLPF) is designed, fabricated and tested. Our device consists of two birefringence plates and a half wave plate. On the front and back surfaces of the OLPF. an antireflection film and an infrared cutting film are plated. The test results show that the antact angle is less than 20°, the transmission in the visible light range and infrared light range is above 90% and less 2% respectively, the high spatial frequency is restrained very well. These reveal that our crystal OLPF can match with the photoelectric image sensor and has a good restraining high spatial performance.