Frequency-agile injection-seeded terahertz-wave parametric generation

Abstract

An injection-seeded terahertz (THz)-wave parametric generator (is-TPG) enables access to low-frequency fingerprints of molecules in the THz frequency region. However, its conventional scan repetition rate (SRR) is limited below 1 Hz. Thus, in this Letter, we propose an electrically controlled tuning system for the is-TPG, which provides high-speed scanning and random hopping agility. We achieved rapid THz frequency scanning on a pulse-by-pulse basis by employing a gain-switched laser diode and a micro-electromechanical system tunable vertical-cavity surface-emitting laser as the pump and seed lasers. A THz spectrum was acquired with a 10 times higher SRR of 10 Hz for the 1.6–3 THz range with a sampling resolution of 4.6 GHz.

Non-collinear phase-matching method for stimulated polariton scattering based on cross-pumping

“…While quasi-phase matching has limited frequency tuning range, non-collinear phase matching is commonly used in THz wave parametric sources. Currently, non-collinear phase-matched THz wave parametric sources utilize either parametric oscillators [6] or seed-injected parametric generators [7] for frequency locking and tuning of Stokes light and THz waves. Parametric oscillators offer advantages such as simplicity, low cost, and high efficiency.…”

Wide dynamic range and real-time reagent identification and imaging using multi-wavelength terahertz parametric generation and machine learning

“…Methods that have been proposed for real-time measurement include the use of a single-frequency source 6 – 8 , THz time-domain spectroscopy (THz-TDS) 9 – 11 , and multi-wavelength fast-switching injected-seeded THz parametric generation 12 – 16 .…”