Small-angle beam deviation with high resolution using gratings
- 物理技术－会议论文 
Small-angle beam deviation has many applications and is conventionally performed by wedge prisms. The usual method suffers from a disadvantage that the manufacturing tolerances limit the resolution to about an arc second. The paper presents a new technique of using low frequency gratings to realize small-angle beam deviation with higher resolution. By rotating a grating placed in the laser beam path, the deviation of the diffracted light beams can be controlled. Using the proposed method, very small beam deviation angle can be achieved under large grating rotation angle, resulting in high reduction ratio. Theoretical analysis shows that as long as the grating period is large enough, the reduction ratio can be much higher than that given by a wedge prism. The theoretical result has been verified experimentally using a holographic grating with 7.25 mu m period placed in a Mach-Zehnder interferometer.