基于马赫曾德干涉原理,设计搭建了可调制与放大干涉条纹的光压测量装置.由频率和功率可调制脉冲激光产生光压,使真空中两面高反镀铝薄膜产生微小形变(位移),从而使由氦氖激光器发射、经半反半透镜分束的参考光和信号光的光程差改变,即干涉条纹发生改变.用CCD记录干涉条纹位移量,数据处理获得干涉条纹位移量和薄膜形变量的关系,计算出脉冲激光在薄膜处的光压.分别讨论了脉冲激光入射角度、频率等参量对检测结果的影响,并通过双角度入射方法消除了热辐射效应的影响.该检测装置可测得最小光功率为15.0mW所产生的光压大小为13.42μPa,线性工作范围为15.0mW(13.42μPa)至200mW(1179μPa),且工作稳定、灵敏度高,测量结果准确.
A device of light pressure detection was designed.The device based on Mach-Zehnder interference theory,and had modulation and amplification interference optical path.The deformation(displacement)of double reflection aluminum film caused by the laser pulse with different frequency and power.The light generated by HeNe laser was split to the reference light and the signal light by a semireflecting and semi-transmitting mirror.The optical path difference of the reference light and the signal light was changed because of the thin film shift.Therefore,it caused the movement of interference fringes.The displacement of interference fringes were recorded by CCD,and then the relationship of fringes movement and the film deformation was calculated.At last,the light pressure was obtained.The effects of pulsed laser incident angle,frequency and other parameters were discussed in detail and the thermal radiation effect is eliminated by using the method of double incidence angle.The device could measure the minimum pressure(13.42μPa)produced by the minimum optical power of 15.0mW.The linear range is from 15mW(13.42μPa)to 200(13.42μPa).The device works steadily,with high sensitivity and accuracy.