| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical device capable of removing a side lobe from an ultra-resolved condensing spot and having high light utilization efficiency. SOLUTION: This device is equipped with linearly polarized light 102, a spatial optical modulation element 103, a polarizing beam splitter 106, a 1/4 wavelength plate 107, condensing lenses 108 and 111, a reflection member and a photodetector 112. The element 103 is constituted of at least a part functioning as a diffraction type lens element 104 and a part functioning as a phase modulation element 105, and the functions of the diffraction type lens element and the phase modulation element are controlled according to an electrical signal, and the part functioning as the phase modulation element acts on a nearly circular area centering an optical axis of luminous flux condensed by the 1st condensing lens 108. |
