双折射调谐器设计的等色图原理

提出双折射调谐器设计的等色图方法，给出原理。分析表明当晶片光轴处在以折射光线为轴线、顶角为４５°的圆锥面上时，双折射调谐器具有最快的波长调谐速率；当光轴位于过折射光线并与入射面成４５°或１３５°的平面内时，调谐器抑制非所需波长的能力最强。由此给出光轴相对晶片表面的两个优化取向，对石英晶片它们分别为１８．７１２°和５９．９２２°。文中还给出了三块晶片组合的调谐器的设计例子，对其调谐特性进行了简要的讨论。

Isochromatic Principle of Birefringent Filter Design

The isochromatic principle of birefringent filter (BRF) design is proposed in this paper. Theoretical analyses show that the BRF has the maximum tuning rate when the optic axis is located on the cone with its symmetric axis being on the refracted ray and apex of 45°; and the rejection of unwanted wavelength of BRF becomes the maximum when the optic axis is in the plane which contains the refracted ray and makes the angle of 45° or 135° with respect to the incident plane. In the result, there are two optimum orientations of optic axis with respect to the plate surface. For quartz crystal BRF, the two angles are 18.712° and 59.922°. A design example of three-plate-BRF is given together with a brief discussion about its tuning characteristics.