| 摘要 |
The present invention relates to an apparatus and a method for detecting an amount of depolarization of a linearly polarized beam transmitted by a birefringent medium in the direction of the optical axis thereof. The apparatus comprises a first beam splitter (7) for separating an on-axis portion (2) of said linearly polarized beam into the orthogonal components (3,4), two photodetectors (8,9) for detecting each component (3,4), a second beam splitter (12) for separating an off-axis portion (11) of said linearly polarized beam into the orthogonal components (15,16), wherein said second beam splitter (12) is disposed off-axis of the incident linearly polarized beam (1), a second set of photodetectors for detecting the components (15,16) separated by said second beam splitter (12), and a subtracting device (17) for substracting the signals received by said second set of photodetectors (13,14) from the respective signals received by the first two photodetectors (8,9). <IMAGE> |
