Abstract: A device and a method for measuring a thermal load caused by energy transfer upconversion in a laser gain crystal. Increasing the pump power multiple times so that the power meter obtains multiple thresholds for a single-frequency laser; obtaining an average pump threshold of the output laser; obtaining cavity parameters of the single-frequency laser; obtaining thermal focal lengths on the tangential and sagittal planes of the laser gain crystal inside the single-frequency laser; obtaining individual ABCD matrices of the laser system on the tangential and the sagittal planes; obtaining a thermal load at the threshold based on the ABCD transfer matrix of the laser gain crystal on the tangential plane, the ABCD transfer matrix of the laser gain crystal on the sagittal plane, and the average pump threshold of the laser system; obtaining a thermal load caused by ETU at threshold based on the thermal load at the threshold.

Abstract: The present disclosure discloses a method of preparing tris-(2-chloroethyl)phosphite, comprising: continuously pumping phosphorus trichloride and ethylene oxide into a tubular pre-mixer for pre-mixing, respectively, and starting a refrigerant cooling unit of the microchannel reaction device simultaneously, to obtain a product tris-(2-chloroethyl)phosphite after complete reaction. The method according to the present disclosure not only significantly improves the content of the esterification product, thus increasing the production efficiency by 10 to 100 times than that of an ordinary tank reactor, but also reduces the residence time of the esterification product in the reactor from 110 hours to several minutes.