Observation of waveguide Fabry-Perot lasing in highly efficient Si nanocrystals

A luminescent Si nanocrystal (SiNC) thin film with photoluminescence quantum yield (PLQY) > 70% was made by using hydrogen silsesquioxane (HSQ), followed by long-time high-pressure hydrogenation. A net optical gain of 524 +/- 21 cm(-1) was obtained by means of variable stripe length-shifting excitation spot (VSL-SES). A rectangularly shaped SiO2 Fabry-Perot (F-P) cavity with size of 1.5 mu m (width) x 0.7 mu m (height) x 2000 mu m (length) was made on top of the SiNC thin film. The waveguide F-P device was pumped with a 400 nm femtosecond pulsed laser. A threshold behavior of the light emission intensity as a function of the pumping power was observed. Other lasing characteristics including spectral narrowing, polarization of the emission, and small emission angle were also observed beyond the threshold pumping power.

Automated summary

A luminescent Si nanocrystal thin film with high photoluminescence quantum yield was successfully fabricated, achieving a net optical gain structure and threshold behavior under optical pumping. Various laser characteristics were observed, such as spectral narrowing, polarization, and small emission angles.