Jordan Wachs
Ball Aerospace & Technologies Corporation
A new architecture for spectrally resolved long baseline interferometry is presented. Utilization of a frequency comb reference allows coherent detection and digitization of the optical field within the full spectrum of the frequency comb. The broadband, coherent nature of the frequency comb allows narrow frequency channels to be down-converted to and measured at RF frequencies, and coherently added in the digital domain — resulting in an SNR that is comparable to that of traditional direct detection interferometers, but without the need for nanometer scale optical path length control for beam combination purposes or the Terabit/sec data rates necessary for sampling the optical field directly.
Spectral sensitivity of the system allows radial velocimetry measurements sensitive to redshift on the order of several Hz, which is sufficient to resolve relative velocity change on the order of mm/sec. Direct spectroscopic measurements with this system will be sensitive enough to detect the presence water, methane, and other compounds with absorption features within the frequency comb spectrum. Due to the nature of this broadband coherent detection scheme, all spectral information is inherently present in all measured data, allowing simultaneous imaging, velocimetry, and spectroscopy measurements.
This paradigm shifting technology will provide extreme spatial resolution as well as direct spectroscopic and radial velocimetry measurements without the need for THz processing or nanometer class positional stability and control.
