Patent ID: 8233101

Claim:
A laminated wave plate comprising a first wave plate with a phase difference of Γ 1 =180° with respect to a designed wavelength λ 0 and a second wave plate with a phase difference of Γ 2 =180°, in which the first wave plate and the second wave plate are arranged and laminated so that optical axes thereof intersect each other, wherein when in-plane bearing angles of optical axes of the first and second wave plates are represented by θ 1 and θ 2 , an angle formed by a polarization direction of the linearly-polarized beam incident on the laminated wave plate and a polarization direction of a linearly-polarized beam output from the laminated wave plate is represented by φ, and an optical axis adjustment amount is represented by a, the following expressions are satisfied: θ 2 =θ 1 +φ/2; θ 1 =φ/4+ a; θ 2 =3φ/4− a ; and 0<a≦a max , wherein the maximum value a max of the optical axis adjustment amount satisfies the following expressions in the designed wavelength range of 400≦λ 0 ≦490 nm: a max =A 0 +A 1 ·φ+A 2 ·φ 2 +A 3 ·φ 3 +A 4 ·φ 4 +A 5 ·φ 5 ; A 0 =0.00001548; A 1 =0.0427887; A 2 =−0.000385; A 3 =1.723×10 −6 ; A 4 =−4.19×10 −9 ; and A 5 =4.086×10 −12 , satisfies the following expressions in the designed wavelength range of 490≦λ 0 ≦520 nm: a max =A 0 +A 1 ·φ+A 2 ·φ 2 +A 3 ·φ 3 +A 4 ·φ 4 +A 5 ·φ 5 +A 6 ·φ 6 +A 7 ·φ 7 ; A 0 =0.00006705; A 1 =17.699248; A 2 =−0.16963; A 3 =0.0006754; A 4 =−1.4×10 −6 ; A 5 =1.68×10 −9 ; A 6 =−1.1×10 −12 ; and A 7 =2.72×10 −16 , and satisfies the following expressions in the designed wavelength range of 520≦λ 0 ≦800 nm: a max =A 0 +A 1 ·φ+A 2 ·φ 2 +A 3 ·φ 3 +A 4 ·φ 4 +A 5 ·φ 5 +A 6 ·φ 6 ; A 0 =0.00003014; A 1 =5.4681617; A 2 =−0.038557; A 3 =0.0001094; A 4 =−1.56×10 −7 ; A 5 =1.106×10 −10 ; and A 6 =−3.13×10 −14 .