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.