Laser Doppler Vibrometry (LDV) is a non-contact optical technique that measures the high frequency vibrations of surfaces by analysing the Doppler shift of laser light. A laser beam is focused onto a sample and the reflected light is compared to a reference beam. This provides information on the velocity, displacement, and phase of the surface vibrations without physical contact. LDV is useful in fields such as structural analysis, vibration testing, and acoustic research, as well as the characterisation of MEMS devices, piezoelectrics and surface acoustic wave devices.