Tuning of the intersubband absorption in a shallow InAs/InP quantum wire by a transverse electric field

• The intersubband absorption energy increases with the tilt angle of field.
• Shallow quantum wire leads to the strong polarization anisotropy of absorption.
• Intersubband strength of y-polarized light decreases with the tilt angle of field.
• Intersubband strength of x-polarized light first increases and then decreases.

Intersubband absorption in a shallow InAs/InP quantum wire (QWR) under a transverse electric field perpendicular to the wire axis is investigated theoretically using the plane wave method in detail. The transverse field is oriented either parallel or perpendicular to the height direction of QWR. The intersubband absorption energy increases with increasing the tilt angle of field along the height direction. The large cross-sectional ratio of QWR leads to the strong polarization anisotropy of the intersubband absorption, which is sensitive to one polarization of light along the width direction while it is insensitive to one polarization of light along the height direction. The intersubband oscillator strength of polarized light along the width direction decreases as the tilt angle of field increases whereas that of polarized light along the height direction first increases until it reaches a maximum, and then decreases. A transverse applied field is shown to provide an efficient tool to tune the wavelength and output of the intersubband device of shallow QWR.