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arXiv · 1607.05897

Characterization of very narrow spectral lines with temporal intensity interferometry

Peng Kian Tan·Christian Kurtsiefer
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Abstract

Context: Some stellar objects exhibit very narrow spectral lines in the visible range additional to their blackbody radiation. Natural lasing has been suggested as a mechanism to explain narrow lines in Wolf-Rayet stars. However, the spectral resolution of conventional astronomical spectrographs is still about two orders of magnitude too low to test this hypothesis. Aims: We want to resolve the linewidth of narrow spectral emissions in starlight. Methods: A combination of spectral filtering with single-photon-level temporal correlation measurements breaks the resolution limit of wavelength-dispersing spectrographs by moving the linewidth measurement into the time domain. Results: We demonstrate in a laboratory experiment that temporal intensity interferometry can determine a 20 MHz wide linewidth of Doppler-broadened laser light, and identify a coherent laser light contribution in a blackbody radiation background.

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Peng Kian Tan, Christian Kurtsiefer. 2016-07-20. Characterization of very narrow spectral lines with temporal intensity interferometry. https://doi.org/10.1093/mnras%2Fstx968

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