A non-linear optical pumping detection apparatus and a non-linear optical absorption cross-section measurement method, which can implement simultaneous measurement of degenerate and non-degenerate non-linear absorption cross-section spectrums. The measurement process is automated, and the measurement process is efficient and fast. The operating band is 380 nm to near-infrared 1064 nm, so that non-linear performance measurements of a ultra-continuous wide spectrum can be achieved. A zoom optical system with a relatively large entrance pupil diameter is used as a weak signal acquisition lens, which can effectively extract a weak signal from background noise; and at the same time, the root mean square diameter of an image point on a shaft of the zoom optical system is 100 microns to 150 microns, and a divergence angle 2α of the image point on the shaft is 30.6 degrees, which well match an optical fiber coupling condition, thereby improving the coupling efficiency of spatial light coupling into an optical fiber, and greatly improving the measurement sensitivity.
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