Possibility of Heterodyne Correlation Interferometry with a Tunable Laser and Absolute Frequency Measurements

Abstract

We consider the possibility of measuring the true width of the narrow optical spectral lines of astrophysical lasers. The lines should have a subDoppler spectral with of 30–100 MHz or even less. To make measurements with spectral resolution better than 10⁷ and angular resolution better than 0.1 arcsec we suggest to use the ground-based Brown-Twiss-Townes optical heterodyne intensity correlation interferometry with the possibility of absolute frequency measurement. The estimates made of the S/N ratio for optical heterodyne astrophysical laser experiments imply that it should be feasible.