The uniformity of optical coatings becomes more and more important as large diameter optical devices are widely used. Absorption loss in optical components, particularly in optical coatings, is a limiting factor in high-power laser applications. This article analyzes the main factors, which affect the spatial resolution of three techniques for surface absorption loss measurement, including the photothermal deflection technique, the surface thermal lens technique, and the photothermal detuning technique. The influence of the size of the heating and probe beam on the photothermal detuning technique is studied in detail. Experiments are conducted to study the photothermal signal of the photothermal detuning technique for absorption measurement of the optical coating point by point. The results show that the main factors, which affect the spatial resolution of imaging measurements for absorption loss of coatings, are the heating beam size and the step accuracy of the sample translation stage. The heating and probe beam sizes has a significant impact on the application of the photothermal detuning technique. Experimental result shows that the photothermal detuning technique can be used for imaging of absorption loss measurements of optical coatings. The results provide theoretical and experimental supports for further application of the photothermal detuning technique.
1.Chongqing Univ Posts & Telecommun, Coll Opt Elect Engn, Chongqing 400065, Peoples R China 2.Chinese Acad Sci, Inst Opt & Elect, Chengdu 610209, Sichuan, Peoples R China 3.Chongqing Univ, Educ Minist China, Key Lab Optoelect Technol & Syst, Chongqing 400044, Peoples R China
Hao, Honggang,Rao, Min,Li, Bincheng,et al. Study on the Spatial Resolution of Imaging Technique for Absorption Loss Measurement of Optical Coatings[J]. INTERNATIONAL JOURNAL OF THERMOPHYSICS,2013,34(8-9):1652-1660.