Suppression of Auger recombination in long-wavelength quantum well W-structure lasers

Using picosecond pulses from a free-electron laser, we have carried out a pump-probe determination of Shockley-Read-Hall (SRH) and Auger free-carrier recombination lifetimes in two long-wave (6–7 μm) W-structure laser with ${\mathrm{I}\mathrm{n}\mathrm{A}\mathrm{s}/\mathrm{G}\mathrm{a}}_{1-x}{\mathrm{In}}_x\mathrm{S}\mathrm{b}/\mathrm{I}\mathrm{n}\mathrm{A}\mathrm{s}/\mathrm{A}\mathrm{l}\mathrm{S}\mathrm{b}$ active regions. The SRH coefficient is nearly constant $(A\approx 4.0\times {10}^8{\mathrm{s}}^{\mathrm{-}1}),$ while the Auger coefficient has an upper limit of $C=4.0\mathrm{}\times {10}^{-27}$ to $2.2\times {10}^{-27}{\mathrm{cm}}^6/\mathrm{s}$ in the temperature range 40–230 K. This represents an order of magnitude Auger suppression compared to type-I III-V semiconductors with the same energy gap.