近红外偏振干涉相位补偿器的稳定性

Stability of Phase Compensator in Near-infrared Polarized Interferometer

相位补偿器是偏振干涉仪的核心部件,其稳定性直接影响偏振干涉光谱仪的可靠性.本文分析了相位补偿器的光程差相对灵敏度、光楔倾斜误差、斜入射角误差和温度适应性等指标,并给出相应的误差容限计算公式.研究表明：相位补偿器移动光楔沿运动方向的抗干扰能力是经典迈克尔逊干涉仪的2/Δnsinθ倍,抗倾斜能力是经典迈克尔逊干涉仪的1.75/Δn倍;当入射光以微量倾斜误差入射后,相位补偿器不会产生额外的附加光程差;―20~85℃范围内的温度变化对相位补偿器产生的最大光程差误差为1.8μm,具有很高的热稳定性;当光楔角为30°时,干涉仪在性能、尺寸和成本之间达到均衡;晶体材料的双折射率差通常远小于1,偏振干涉的稳定性更加明显.本研究为相位补偿器在更为复杂的环境中的应用奠定了基础.

Phase compensator is a key element in the polarized interferometer,whose stability has a directive influence on the reliability of the polarized interference spectroscopy.The specification of the phase compensator such as the relative sensitivity of optical path difference,the tilted error tolerance of optical wedge,the oblique incidence angle error tolerance and the temperature adaptability were studied,and the corresponding calculated formulas were derived.The anti-interference ability of the moving optical wedge is 2/Δnsinθtimes stronger than the classical Michelson interferometer.The ability of the moving wedge to resist the inclination is 1.75/Δntimes higher than classic Michelson interferometer.After light′s incidence with small angle,there are no additional optical path.The greatest optical path distance error of the phase compensator is 1.8μm when the temperature changes from―20℃to 85℃,which has a good thermal stability.The angle of the wedge is also an important parameter to affect the phase compensator.If setting the angle of the wedge as 30°,agood balance between performance,size and cost may be achieved.The birefringence difference of crystal material is smaller than one,so the stability advantages of the polarized interferometer are very obvious which build up agood basis for its field application with complicated surroundings.