Measuring angular rotation via the rotatory dispersion effect

Abstract

We propose a scheme for an ultrasensitive weak measurement system with an ultrasmall rotatory dispersion effect to measure angular rotation. Estimation of angular rotation is obtained by the shift of the center wavelength. In our scheme, we obtain a continuously adjustable coupling strength and show that our system provides a 13 times higher sensitivity of 38 840 nm/rad compared with previous work. Here we demonstrate that our scheme may offer an optimal weak value ${A}_{w}$ in practice and outperforms conventional measurements in the presence of technical noise. The precision achieved by optimized weak value amplification (WVA) is about three times higher than that of a polarimeter. Our work extends the working regime of WVA. Its simplicity and robustness clear the way for widespread use of WVA involving measurements with commercial cameras and small signals.