Self-feedback weak measurement for highly-sensitive, wide-range phase detection

Abstract

High-precision phase measurement is a key technology for modern physics research and applications. In this work, a method of self-feedback measurement based on weak measurement is proposed to break through the contradiction of mutual constraints between sensitivity and range of traditional weak measurement techniques. By leveraging real-time feedback on the spectral distribution characteristics and wavelength shift of the output light and automated reference phase modulation, this method achieves high-sensitivity target phase measurement (with an experimental accuracy of $10^{-5}$ rad) and adaptive extension of the measurement range. The experimental verification shows that the measurement system can always maintain a highly-sensitive working state through feedback control.