| 摘要 |
PROBLEM TO BE SOLVED: To obtain stable evanescent light by providing a means for separating luminous flux on a 1st surface and a deflecting means for totally reflecting and making each luminous flux incident on a 2nd surface. SOLUTION: A beam splitter surface 4 is provided to form the angle of about 45 deg. with a surface 2 on a plane 3 perpendicular to the surface 2. The luminous flux nearly perpendicularly made incident on the surface 2 is separated to the luminous flux 1 nearly straight advancing as it is and the luminous flux 2 orthogonally crossing the luminous flux 1 on the surface 4. The luminous flux 1 is deflected on a reflection surface 6 and made incident on a surface 7. Since the surface 6 forms the angle of about 22.5 deg. with the surface 3, the incident angleθof the luminous flux 1 becomes about 45 deg. to satisfy the total reflection condition, then the luminous flux 1 is totally reflected on the surface 7 so as to generate the evanescent light. A surface 8 forms the angle of 15 deg. with the surface 2 and the angle of 75 deg. with the surface 7, and the incident angle of the incident light on the surface 8 is about 30 deg.. The luminous flux 1 is transmitted and refracted by the surface 8 and emitted to the outside of the prism stage 1. Meanwhile, the luminous flux 2 is deflected by a surface 5 forming the angle of about 22.5 deg. with the surface 3, totally reflected on the surface 7 so as to generate the evanescent light, and emitted from a surface 9 to the outside of the prism stage 1.
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