Ultrafast, broadband and tunable terahertz reflector and neutral density filter based on high resistivity silicon
Idioma
en
Article de revue
Este ítem está publicado en
Optics Express. 2022, vol. 30, n° 11, p. 18995
Optical Society of America - OSA Publishing
Resumen en inglés
We report THz transmission and reflection properties of an ultrafast optically excited highly resistive silicon wafer. Amplified Ti:Sapphire femtosecond laser pulses at 800 nm were used to create fluence-dependent carrier ...Leer más >
We report THz transmission and reflection properties of an ultrafast optically excited highly resistive silicon wafer. Amplified Ti:Sapphire femtosecond laser pulses at 800 nm were used to create fluence-dependent carrier density on the front surface of the wafer which modifies the dielectric properties at the THz frequencies. Time-resolved experiments in the optical pump-THz probe configuration were conducted in which THz pulses reflected off from the surface at 0°and 45°angles of incidence make it possible to measure the pump-fluence dependent ultrafast evolution of the reflection and transmission coefficients in 0.5-6 THz range. An analytical model, where both the Drude contributions from the photoexcited electrons and holes account for the change of the dielectric constant of the photoexcited silicon, has been used to evaluate the THz reflection and transmission coefficients at steady state. Thus obtained results match well with the experimental results and demonstrate an all-optical means to convert a silicon wafer into an ultrafast, tunable and broadband neutral density filter or reflector in the THz frequency range.< Leer menos
Palabras clave en inglés
TeraHertz
Index modulation
Orígen
Importado de HalCentros de investigación