Rapid optical thin-film absorption measurement based on high-power laser thermography method

The precise measurement of absorptance in optical thin films is crucial for high-power laser systems across scientific, industrial, and defense applications. However, the present absorption measurement method is limited by measurement speed or accuracy. A high-power laser thermography (HLT) method is developed to measure optical thin-film absorption rapidly. The principle of the method consists of applying a high-power laser to the coatings and monitoring the temperature of the sample with an infrared camera. Combining sample calibration, absorption of samples is measured quantitatively and rapidly. A set of optical components is simultaneously measured by the HLT method and laser calorimeter method; the difference is below 1 ppm, indicating the high reliability of the absorption data with ppm-level measurement accuracy. It can be applied for high-precision absorption measurement and thin-film process improvement.