Low noise laser-based T-ray spectroscopy of liquids using double-modulated differential time-domain spectroscopy
Year: 2004
Type: article
Abstract: Liquid transmission studies at terahertz frequencies (0.1–10 THz) are valuable for understanding solvation dynamics of salts, exploring long-range structure in mixtures and probing biomolecules in suspension. T-ray (or THz) time-domain spectroscopy, based on terahertz pulse generation from ultrafast lasers, is a sensitive technique for measuring material parameters in this frequency range. This paper proposes and demonstrates a novel technique for increasing the sensitivity and repeatability of liquid studies with T-ray time-domain spectroscopy (TDS), reducing relative parameter measurement errors below 0.0001. The proposed technique combines dual-thickness liquid measurement with rapid modulation (double-modulated differential TDS) to reduce the effect of both thickness-measurement errors and T-ray noise errors below 0.0001. The possible reduction in error is calculated and a liquid differential TDS (DTDS) prototype is demonstrated, incorporating amplitude and mean detection for near-simultaneous measurement of two T-ray waveforms.
Institutions: The University of Adelaide, Rensselaer Polytechnic Institute
Language: English
Subfield: Electrical and Electronic Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: bronze
OpenAlex ID: W2098478441