| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a wave plate capable of obtaining a preferable phase conversion characteristic over a wide wavelength range. <P>SOLUTION: The wave plate includes a glass substrate 1 and an aluminum oxide film 3 having linear grating groove patterns which is formed on the glass substrate 1. The period L (μm) and the duty ratio De being the ratio of an actual width of an oxide aluminum film 3 between adjacent grating grooves to the period L (μm) of the grating groove patterns are set within the first range F2 specified by following four formulas: L1≤0.65, L1≥2×10<SP>-14</SP>e<SP>31.263De</SP>, L1≤6.0317De<SP>2</SP>-10.352De+5.0516, (De-0.85)<SP>2</SP>/0.44<SP>2</SP>+(L1-0.41)<SP>2</SP>/0.39<SP>2</SP>≤1. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
