🔴 Photonic Doppler Velocimetry: Beat Frequency, Fringe Counting and Mirror Velocity (2D)

Top view of a laser probe bouncing off a moving mirror. Choose the wavelength, stroke, motion type and reference offset, and watch the detector beat signal, the frequency shift 2v over lambda, the fringes counted and the spectrum peak. The motion model is the same module as the 3D velocimetry page; the signal and spectrum are computed here, with four in-page numerical checks.