Dual wavelength brillouin laser terahertz source stabilized to carbonyl sulfide rotational transition

TL;DR

This paper reports the stabilization of a dual-wavelength Brillouin laser terahertz source to a specific molecular rotational transition, achieving high stability and spectral purity for applications in spectroscopy and metrology.

Contribution

The authors demonstrate a novel stabilization method for a dual-wavelength Brillouin laser terahertz source using a molecular transition of carbonyl sulfide, enhancing stability and spectral purity.

Findings

Achieved an instability of 1.2×10⁻¹²/√τ in the stabilized terahertz source.

Demonstrated high spectral purity and stability suitable for precision spectroscopy.

Discussed limitations related to signal-to-noise ratio and intermodulation effects.

Abstract

Optical-based terahertz sources are important for many burgeoning scientific and technological applications. Among such applications is precision spectroscopy of molecules, which exhibit rotational transitions at terahertz frequencies. Stemming from precision spectroscopy is frequency discrimination and stabilization of terahertz sources. Because many molecular species exist in the gas phase at room temperature, their transitions are prime candidates for practical terahertz frequency references. We demonstrate the stabilization of a low phase-noise, dual-wavelength Brillouin laser (DWBL) terahertz oscillator to a rotational transition of carbonyl sulfide (\ce{OCS}). We achieve an instability of $1.2\times10^{-12}/\sqrt{\tau}$, where $\tau$ is the averaging time in seconds. The signal-to-noise ratio and intermodulation limitations of the experiment are also discussed. We thus demonstrate a highly stable and spectrally pure terahertz frequency source. Our presented architecture will likely benefit metrology, spectroscopy, precision terahertz studies, and beyond.