| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a diffraction element in which orders at each of which the diffraction efficiency is maximum are different, when lights of a plurality of lights having different wavelengths are made incident. <P>SOLUTION: A diffraction element 100, in which unit regions 110 each having a grating-shaped unevenness are periodically arranged in X-direction, is formed in such manner that the widths in X-direction of a small region 110a, a small region 110b, and a small region 110c constituting the unit region 110 are equivalent, and further, each of the phase difference ϕ(1) being the phase of a light transmitting the small region 110b based on the phase of a light transmitting the small region 110a and the phase difference ϕ(2) being the phase of a light transmitting the small region 110c based on the phase of the light transmitting the small region 110a becomes an integer multiple of π (ϕ(1)≠ϕ(2)). Thereby, as a combination that the symbols of an order at which the diffraction efficiency is maximized are different in lights having different wave lengths is generated, a diffraction element 100 capable of performing deflection separation at a large angle in comparison with a conventional diffraction grating without making the grating pitch small can be obtained. <P>COPYRIGHT: (C)2010,JPO&INPIT |
