Ultrafast Terahertz Spectroscopy and Imaging

Three independent femtosecond laser systems used for generating ultrafast pulses in the mid-IR (and THz) through the UV; infrared and visible multi-element focal plane array cameras and instrumentation for capturing the transient spectra of samples with a single laser pulse; detection systems capable of making accurate time-resolved amplitude and phase measurements on Thz pulses as they interact with samples; crystals for nonlinear frequency conversion.

Apparatus includes two femtosecond laser systems (YVO₄) solid-state pumped 20-femtosecond Ti:sapphire oscillators and KHz Ti:sapphire regenerative amplifiers with a mid-IR OPA for generating ultrafast pulses in the far-IR through UV; visible and near-IR CCD multichannel detector arrays and instrumentation for capturing transient spectra and up-converted THz images of samples.

Ti-sapphire kilohertz laser system used for generating 2 watts at 805nm pulses for time-resolved THz spectroscopy (background table). The regenerative amplifier (center) is pumped by a 20 watt nanosecond laser. The OPA (foreground) is used to generate tunable visible and near-infrared excitation pulses for pump-Thz probing of photovoltaics as well as mid-IR probes for the TRIR apparatus.

Time-resolved THz spectrometer for spectral determinations of samples (0.2 to 10 THz) and transient spectroscopy of bimolecular, photovoltaic, and materials characterization.

Terahertz imaging apparatus employing high-power pulsed GaAs antenna generator and object transmission and reflection geometries for hyperspectral studies relevant to homeland security applications.