The response speed and fatigue characteristics of a pulsed 778 nm→420 nm conversion in rubidium vapor

•The response speed of the 778 nm→420 nm conversion in Rb vapor is examined with multi-mode pulse shape of the 778 nm laser, and results show the ability of resolving pulses as short as 0.8 ns.•A fatigue phenomenon is found in the 778 nm→420 nm conversion process.•The mechanism of the fatigue phenomenon is found to be related to the lifetime of the 62P3/2 level, and the recovery time from the fatigue is measured to be 227 ns.

A strong 778 nm→420 nm conversion was realized in Rb vapor. With the help of the multi-spike structure of the 778 nm pumping laser, the response speed of the 778 nm→420 nm conversion was successfully measured. Experimental results showed that the conversion was a high-speed process, with a response bandwidth of 1 GHz. In addition, fatigue phenomenon of the 778 nm→420 nm conversion under strong pumping was observed, and the recovery time of such fatigue was measured with a dual-pump method.