| 摘要 |
An optical device comprising an optical focusing system (104) for focusing an incident linearly polarized beam (10), a light-separating element (701) for separating from the incident light a light beam reflected by a light reflecting member (105) disposed near the focal plane of the optical focusing system (104), and a light sensing element (704) for sensing the separated light beam (12). In the incident light path of the linearly polarized beam (10), there is provided an optically rotating element (103) which is capable of rotating by about 90 degrees the axis of polarization of a portion of the effective light beam (11) utilized by the optical focusing system (104) of the linearly polarized beam, and of which the optically rotating ability is controlled by an electric signal. Moreover, a linearly polarized beam detector element (703) is provided in the optical path of the separated light beam (12). This makes it possible to accomplish a super-resolution without attenuating the optical intensity. The SN ratio of detection signals can be improved by simply removing side lobes from the separated light beam of reflected light. Sensing light can also be produced in a state where the opening of the optical focusing system is changed over. <IMAGE> |
