Coexistence of excitonic lasing with electron-hole plasma spontaneous emission in one-dimensional semiconductor structures

We report that excitonic lasing gain coexists with spontaneous optical emission characteristic of an electron-hole plasma in highly photoexcited one-dimensional semiconductors. The experiments probe quantum T-wire laser structures optimized for high photoexcitation. Evidence of dense electron-hole plasma is clearly seen in the spontaneous recombination measured when lasing emission displays distinct excitonic character. These findings differ strikingly from those in higher dimentional semiconductors, and offer insights on optical processes considered by recent theories of dense electron-hole plasmas.