1.55 μm laser excitation of narrow bandgap semiconductors for terahertz emission
Abstract
A 1.55 μm femtosecond fiber laser was used to excite p- and n-type InAs and InSb semiconductors at the reflection geometry. Results revealed that at this excitation wavelength, InAs showed a much stronger THz emission. This contradicts previous studies wherein InSb has been demonstrated to have a stronger THz emission. However, using a Si lens coupler, significant enhancement of the THz wave was observed from InSb semiconductor as compared to InAs. Significant increase in the THz emission was also seen from InSb under a magnetic field. The combination of the InSb emitter and the femtosecond fiber laser system provides a stable and compact THz system.