Superfluorescent emission in electrically pumped semiconductor laser

TL;DR

This paper demonstrates superfluorescent emission in electrically pumped InGaN/InGaN quantum well lasers, showing a transition from spontaneous emission to superfluorescence and lasing, with characteristic spectral and power behaviors.

Contribution

It provides the first experimental evidence of superfluorescence in electrically pumped semiconductor lasers with detailed spectral and power analysis.

Findings

Superlinear growth of SF pulse power with increased current

Spectral broadening and hyperbolic secant envelope during SF

Red shift of emission wavelength due to e-h pairing

Abstract

We report superfluorescent (SF) emission in electrically pumped InGaN/InGaN QW lasers with saturable absorber. In particular, we observe a superlinear growth of the peak power of SF pulses with increasing amplitude of injected current pulses and attribute it to cooperative pairing of electron-hole (e-h) radiative recombinations. The phase transitions from amplified spontaneous emission to superfluorescence and then to lasing regime is confirmed by observing (i) abrupt peak power growth accompanied by spectral broadening, (ii) spectral shape with hyperbolic secant envelope and (iii) red shift of central wavelength of SF emission pulse. The observed red shift of SF emission is shown to be caused by the pairing of e-h pairs in an indirect cooperative X-transition.