Electric modulation of optical absorption in nanowires

• We studied the optical absorption of nanowires with Rashba effect.
• Absorption peaks for spin-split states show amplitude modulation.
• Amplitude modulation is quadratic in the strength of the electric field.
• These peaks also suffer frequency shifts.
• Other transitions exhibit parallel band effect leading to strong absorption.

We have calculated the effect of an external electric field on the intersubband optical absorption of a nanowire subjected to a perpendicular magnetic field and Rashba effect. The absorption peaks due to optical transitions that are forbidden in the absence of the intersubband coupling experience strong amplitude modulation. This effect is quadratic in electric fields applied along the direction of quantum confinement or perpendicularly to tune the Rashba parameter. The electric field also induces frequency modulation in the associated spectrum. On the other hand, transitions that are normally allowed show, to a large extent, a parallel band effect, and accordingly they are responsible for strong optical absorption.