Multiphoton excitation in spin split two-dimensional electron gas

•The Multiphoton processes have been studied in a magnetically confined 2DEG.•Effect of Rashba spin–orbit interaction has also been taken into account.•Floquet theory is used to study the time-evolution of Rashba system under laser field.•The study may be helpful in optical control of spin-based devices and photodetectors.

The terahertz radiation induced multiphoton excitation processes have been studied in a two dimensional electron gas where the mixing of spin-up and spin-down states of neighbouring Landau levels by Rashba spin orbit interaction results in two new, unequally spaced energy branches. The multiphoton transitions between different quasi-spin branches of electron gas are found to be dominant over transitions involving the states from the same branch. It has been observed that enhancement and power-broadening of absorption spectrum can be effectively tuned by strength and frequency of the laser field as well as the spin–orbit coupling.