| 摘要 |
<p>This invention describes a double-pass optical filter having a pair of reflective surfaces (14, 14') with a pair of optical media (7, 8) of different indices of refraction inserted between the surfaces (14, 14'). Light is then passed through the surfaces and through each of the optical media (7, 8) to obtain selected frequencies. This invention also includes a means (11) for varying the distance between the reflective surfaces (14, 14') so as to tune the filter over a continuous range of frequencies. This continuous simultaneous tuning of two resonant cavities (7', 8') can be achieved by merely displacing one reflective surface relative to another. <IMAGE></p> |
