立方棱镜二向色分光膜消倍频反射峰的设计

立方棱镜二向色分光镜是实现多光谱共光路的重要器件.立方棱镜二向色分光镜因偏振效应而在高级次倍频处出现高反射峰,严重影响了短波区的透过率.利用虚设层概念,设计出了400 nm～900 nm波段高透过、1 064 nm激光波段高反射的立方棱镜二向色分光镜.给出了消除倍频反射峰的有效方法,并成功制作出光学性能优良的样品.采用这种设计方法获得的膜系结构简单,膜层数量少,材料选择广泛,对工艺要求简单,便于工艺实现,可重复性好.

Design of dichroic beam-splitting film coated on cubic prism for removing frequency-doubled reflection peak

The dichroic beam-splitting mirror of cubic prism is an important element to realize multispectrum in one channel. Due to polarization effect, the dichroic beam-splitting mirror of cubic prism produces a high reflection peak at the high-order doubling frequency, which influences the transmittance in short wavelength seriously. A dichroic beam-splitting mirror of cubic prism, which has high transmittance in the range of 400 nm～900 nm and high reflectivity at 1 064 nm, was designed with the dummy layer concept. A valid method to remove the frequency-doubled reflection peak is presented. A sample with good optical performance was fabricated successfully. The film system is easy to be prepared, since its structure is simple, layer number is fewer, material alternatives and process requirement are less strict.