| 摘要 |
In order to protect a delicate photo-detector from high-intensity optical radiation such as from a laser, a device for limiting power to the detector is interposed between the radiation and detector. This device has two embodiments and is made such that high-intensity radiation is totally reflected. In the absence of high-intensity radiation, total reflection is frustrated, and desired radiation passes to the detector. Both embodiments use two prisms with parallel surfaces skewed to incident radiation and with a slightly absorbant optical material between the surfaces. Desired radiation normally passes through the prisms and the material to the detector. In one embodiment, the material is a liquid which vaporizes in response to high-intensity radiation, and in the other embodiment, the material expands and pushes the prisms apart. In either case, transmission of radiation halts, and the radiation is totally reflected by a prism skewed surface.
|
