Ultra-sensitive heterodyne detection at room temperature in the atmospheric windows

Abstract

We report room temperature heterodyne detection of a quantum cascade laser beaten with a local oscillator on a unipolar quantum photodetector in two different atmospheric windows, at 4.8 $\mu$m and 9 $\mu$m. A noise equivalent power of few pW is measured by employing an active stabilization technique in which the local oscillator and the signal are locked in phase. The measured heterodyne noise equivalent power is six orders of magnitude lower than that obtained with direct detection.

18 pages, 10 figures, 6 tables

References in corpus (4)

• Quantum cascade laser frequency stabilisation at the sub-Hz level
• QCL-based frequency metrology from the mid-infrared to the THz range: a review
• A widely tunable 10-$\mu$m quantum cascade laser phase-locked to a state-of-the-art mid-infrared reference for precision molecular spectroscopy
• Highly coherent phase-lock of an 8.1 $\mu$m quantum cascade laser to a turn-key mid-IR frequency comb

Cited by in corpus (1)

• Heterodyne coherent detection of the electric field temporal trace emitted by frequency-modulated comb lasers