| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical device in which the component of a side lobe can be eliminated from a light condensing spot super-resolved. SOLUTION: In the optical device having a coherent light beam and a condensing lens condensing the coherent light, a rotary polarization optical device 103 consisting of a part where the coherent light beam is converted to the linearly polarized light in a θ deg. direction and emitted and a part where the coherent light beam is converted to the linearly polarized light in a nearly (θ-90) deg. direction, and emitted is set, the part where the coherent light beam is converted into the linearly polarized light in the θdeg. direction functions at a nearly circular or rectangular area centering around an optical axis of the effective luminous flux of the coherent light 102 utilized by a condensing lens 107 and a linearly polarized light detecting element 108 detecting a luminous flux emitted from the element 103 is set. |
