Characterization of very narrow spectral lines with temporal intensity interferometry [IMA]

http://arxiv.org/abs/1607.05897


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.

Read this paper on arXiv…

P. Tan and C. Kurtsiefer
Thu, 21 Jul 16
12/48

Comments: 4 pages, 4 figures