THz radiation from narrow bandgap semiconductors by 1.56 μm femtosecond laser excitation

A 1.56 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 still showed a much stronger THz emission that differs from previous studies. However, using permanent magnets and a Si lens coupler, significant enhancement of the THz wave was observed from InSb semiconductor as compared to InAs. The combination of the InSb emitter and the femtosecond fiber laser system provides a stable and compact THz system