| 摘要 |
PROBLEM TO BE SOLVED: To provide a polarizing beam splitter having polarization and separation characteristics high both in reflectance of S polarized component and in transmittance of P polarized component and has a small asymmetry. SOLUTION: In this polarized beam splitter, a dielectric multi-layer film constituted by thin film layers made of relatively high refractance substance and thin film layers made of low refractance substance repeatedly is formed on a joint face of two light transmissive substrates, the dielectric multilayer film includes a first lamination layer having a film configuration of H/L/H/L/H and a second lamination layer having a film configuration of H/L/H/L/H, and an average value of optical film thickness of the thin film layers H and L constituting the first lamination layer is (H1) and (L1) and an average value of optical film thickness of the thin film layers constituting the second lamination layer is (H2) and (L2). A ratio of (H1) to (L1) calculated by using a smaller value among (H1) and (L1) as denominator is R1, a ratio of average value (H2) to (L2) is R2, and a smaller ratio among the ratios R1 and R2 is Q1 and a large ratio among them is Q2. When m=1 to 3 and n=1 to 4, each equation, 0.95m<=Q1<=1.2m, 0.9 (m+n)<=Q2<=1.4 (m+n), 2<=m+n<=5 is satisfied.
|
