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arXiv · 1504.06216

A quantum cascade laser-based mid-IR frequency metrology system with ultra-narrow linewidth and $1\times 10^{-13}$-level frequency instability

Michael G. Hansen·Evangelos Magoulakis·Qun-Feng Chen·Ingo Ernsting·Stephan Schiller
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Abstract

We demonstrate a powerful tool for high-resolution mid-IR spectroscopy and frequency metrology with quantum cascade lasers (QCLs). We have implemented frequency stabilization of a QCL to an ultra-low expansion (ULE) reference cavity, via upconversion to the near-IR spectral range, at a level of $1\times10^{-13}$. The absolute frequency of the QCL is measured relative to a hydrogen maser, with instability $<1\times10^{-13}$ and inaccuracy $5\times10^{-13}$, using a frequency comb phase-stabilized to an independent ultrastable laser. The QCL linewidth is determined to be 60 Hz, dominated by fiber noise. Active suppression of fiber noise could result in sub-10 Hz linewidth.

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Michael G. Hansen, Evangelos Magoulakis, Qun-Feng Chen, Ingo Ernsting, Stephan Schiller. 2015-05-05. A quantum cascade laser-based mid-IR frequency metrology system with ultra-narrow linewidth and $1\times 10^{-13}$-level frequency instability. https://doi.org/10.1364/ol.40.002289

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