Short wavelength (4 <i>µ</i>m) quantum cascade detector based on strain compensated InGaAs/InAlAs

We report on a quantum cascade detector based on nearly strain compensated InGaAs/InAlAs pseudomorphically grown on InP substrate and detecting light at short wavelengths around 4 <i>µ</i>m. The background limited infrared performance (BLIP) condition is met at a temperature of 108 K with a high detectivity of <i>D</i>^*_BLIP =1.2×10¹¹ Jones.