optical coherence-domain reflectometry optical frequency-domain reflectometry A method for determining structure by illuminating an extremely flat surface with light from a pulsed laser and interfering the light reflected from the sample at the Brewster angle with light reflected from a reference mirror. Intereference only occurs when the difference in the optical path lengths between the two mirrors is within the coherence length of the optical source. The frequency of the laser pulse is proportional to the time delay between each of the signals returning. OFDR CHMO:0000214 optical frequency-domain reflectivity optical frequency domain reflectivity optical frequency domain reflectometry