Device for accurately measuring optical lens transmittance in high power laser environment and method

The present invention discloses an optical lens transmittance measuring device which comprises a laser light source, a beam expanding device, a 45-degree optical divider ratio 50/50 film coating beam splitter, a compensation piece, a slit, a first power meter and a second power meter. In the measurement, firstly the laser light source is opened, the readings P1 and P2 of the first power meter and the second power meter are recorded, and a power ratio c=P1/P2 is obtained. Then a lens to be measured is placed in the transmission light path of the optical lens transmittance measurement device, the position and angle of the lens to be measured are adjusted by using the calibration device of the lens to be measured, and the readings P1' and P2' of the first power meter and the second power meter are recorded. Finally, the transmittance T of the lens to be measured is calculated through the following formula T= P2'c/P1'. According to the device and the method, the requirement of light source stability is low, the thickness of the lens to be measured is not required, and the influence of surface reflection before and after light splitting and optical film coating lens film system uniformity on a testing result can be eliminated.