Generalized Doppler effect for high-accuracy frequency shift measurement

Abstract Laser Doppler effect enables a wide range of precision measurements. However, its traditional implementations, including linear, rotational, and vectorial forms, have historically been treated as isolated phenomena, and meanwhile, their accuracy is fundamentally limited by the achievable frequency shift magnitude due to single controllable parameter. Here, we report a generalized Doppler effect that overcomes these limitations and enhances metrological accuracy. Such effect arises when