Picosecond spin relaxation in GaSb/AlSb multiple quantum wells with a $1.55-\boldsymbol{\mu} \mathbf{m}$ energy band gap

GaSb/AlSb multiple quantum wells (MQWs) have the potential advantages for their use as the $1.55-\mu \mathrm{m}$ optical devices. In this paper, we investigated the spin relaxation of two GaSb/AlSb MQWs obtained via time-resolved spin-dependent pump and probe measurements. The spin relaxation times of the GaSb/AlSb MQWs were measured to be 6.7 ps for 48-nm-thick wells and 7.6 ps for 13.4-nm-thick wells at room-temperature (RT). This result demonstrates that the energy band gap of GaSb/AlSb MQWs can be tuned without affecting the spin relaxation time at RT.