Some scientific instruments commonly designated Reflectometer are: Vector Network Analyser (VNA) Spectrophotometer: in optics, an instrument for measuring the reflectivity or reflectance of reflecting surfaces Optical time domain reflectometer Reflectometer (electronics): In electronics, a directional coupler containing matched calibrated detectors in both arms of the auxiliary line, or a pair of single-detector couplers oriented so as to measure the electrical power flowing in both direct… (More on Reflectometer)