| 摘要 |
<p>A variable optical filter comprising, arranged along an optical axis in the order mentioned, a first polarizer, a first phase difference element for causing a phase difference, a variable Faraday rotor for imparting a variable Faraday rotation, a second phase difference element for causing a phase difference, and a second polarizer, wherein when angles formed between the optical axes of the first and second phase difference elements and the transmitting polarization azimuth of the first polarizer are respectively φ1 and φ2, φ1 and φ2are set at different ones. When the rotational direction of the rotation angle θ of the Faraday rotor is positive, an angle δ formed between the polarization transmitting azimuth of the first polarizer and polarization transmitting azimuth of the second polarizer is δ>0, an angle φ1 formed between the poarlization transmitting azimuth of the first polarizer and the optical axis of the first phase difference element is φ1<0, an angle φ2 formed between the poarlization transmitting azimuth of the first polarizer and the optical axis of the second phase difference element is φ2<0, and φ1 and φ2 are set to be φ1≠φ2.</p> |
