In general, I have often seen nonlinear response generated by a pump laser passed through a chi2 material. Can it be possible to get a nonlinear response by the material's own emission?
Dear Danish! You may remember the useful empirical Miller rule: nonlinear response is always proportional linear index refraction so semiconductors are the best material for similar observation. You are going to observe/study the 2-photon excited luminescence as one of majority of nonlinear effects (self-focusing, harmonic generation and other). If You prefer fluorescence use for 2-photon excitation the powerfull pulse (nano,-picosecond duration) laser and You will be happy with results.
It depends on several parameters like the bandgap nature of the SC itself.
It is a very interesting question. The answer is delicate because you do not want the excitation of the SC emission to induce non linearities in the emitted light. But.
A long time ago I made the calculation of the doubling of the light of a candle using a KDP crystal and found that the emitted UV light should be observable. Yet semiconductors do have a larger chi-2 than KDP. My guess is yes there should be second harmonic generated from the intrinsic emission of a semiconductor. Frequency doubling is a good situation as it is easy to filter the fundamental emission and therefore to isolate the very scarce emitted UV photons.
This is what you are looking for "Continuous‐wave operation of a blue vertical‐cavity surface‐emitting laser based on second‐harmonic generation" Appl. Phys. Lett. 68, 1895 (1996).
The latest answer I just found to this question is "Self frequency conversion". Ref. https://www.osapublishing.org/oe/abstract.cfm?uri=oe-21-17-19778
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