Herr, Simon J.Simon J.HerrFolwill, YannickYannickFolwillBuse, KarstenKarstenBuseBreunig, IngoIngoBreunig2022-03-052022-03-052017https://publica.fraunhofer.de/handle/publica/24880410.1364/OL.42.002627Lasing and self-frequency doubling are achieved in a millimeter-sized laser-active whispering-gallery resonator made of neodymium-doped lithium niobate. A low-cost 808-nm laser diode without external frequency stabilization is sufficient to pump the neodymium ions. Laser oscillation around 1.08 mm drives a frequency-doubling process within the same cavity providing green light. The electrical-optical efficiency of the system reaches up to 2×10−4. To the best of our knowledge, this is the first demonstration of combining lasing and 𝜒(2) frequency conversion in a single high-𝑄 whispering-gallery resonator. This approach is general and can be applied to other materials and other nonlinear optical processes.enwhispering Gallery Resonatornonlinear opticsintegrated opticsLaser621535journal article