Design and performance of reflective terahertz air-biased-coherent-detection for time-domain spectroscopy.

When a sample being tested is optically opaque or has a high absorption coefficient, a reflective measurement is often more suitable than a transmission measurement. We report the design and evaluation of a reflective terahertz time-domain spectroscopy (R-THz-TDS), using air as THz wave emitter and sensor, together with air-biased-coherent-detection (ABCD) method for the first time. With an 85 fs pulse amplified laser, we demonstrate a usable bandwidth from 0.

Liquid-crystal-based terahertz tunable Solc filter.

A broadly tunable terahertz Solc-type birefringence filter is demonstrated. The first central passband frequency of the filter can be continuously tuned from 0.176 to 0.