双菱体λ/4消色差相位延迟器的设计

根据菲涅尔全内反射相变理论,给出了双菱体λ/4消色差器的结构设计、性能分析和测量方法.由有效通光孔径和光线追迹设计出BK7玻璃在波长532 nm时相位延迟λ/4的双菱体的结构,用作532 nm至1 064 nm波长范围的标准λ/4相位延迟器.理论分析了入射角变化和波长变化对双菱体相位延迟的影响,当入射角变化限制在±4.3°以内时,其影响得到补偿；波长从532 nm到1 064 nm产生的误差为－0.65°.采用椭偏法中的消光技术,分别实测了双菱体在532 nm和1 064 nm波长下的相位延迟为：90.08±0.14°和88.99±0.1°,可知两不同波长产生的相位延迟误差为－1.09°.

Design of a Birhomb-type Achromatic Phase Retarder

Based on the total-reflection phase transformation theory of the Fresnel reflection,a method of designing,analyzing and fulfilling the measurement of a birhomb-type λ/4 retarder is presented.Based on effective aperture and light trace,a birhomb-type λ/4 retarder at the wavelength of 532 nm made from BK7 glass is designed,which acts as a standard λ/4 phase retarder from the wavelength of 532 nm to 1 064 nm.Retardance errors due to input angle variation and light wavelength variation are theoretically analyzed,which show that the error due to input angle variation can be compensated when input angle is limited within ±4.3°,and due to wavelength variation is －0.65° when the wavelength varies from 532 nm to 1 064 nm.A null technique of ellipsometry is adopted to measure the birhomb at the wavelength of 532 nm and 1 064 nm,respectively.The retardance at 532 nm is 90.08°±0.14° and at 1 064 nm is 88.99°±0.1°,so the retardance error of the two different wavelength is －1.09°.