Realization of higher Precision in Interferometric-weak-value-based Small-tilt Measurement

TL;DR

This paper demonstrates a significant improvement in small tilt measurement precision by combining weak value amplification, a Sagnac interferometer, and balanced homodyne detection, achieving a precision of 3.8 nanoradians.

Contribution

The study introduces a novel combination of WVA, BHD, and interferometry to enhance measurement precision beyond traditional methods.

Findings

Achieved a minimum measurable tilt of 3.8 nrad.

BHD outperforms split detection in SNR.

Combining WVA and BHD improves sensitivity in weak signals.

Abstract

We experimentally realize a great precision enhancement in the small tilt measurement by using a Sagnac interferometer and balanced homodyne detection (BHD) of high-order optical modes, together with the weak value amplification (WVA) technique. Smaller minimum measurable tilt (MMT) and higher signal-to-noise ratio (SNR) can be obtained by using BHD, compared with the split detection (SD). The precision of 3.8 nrad can be obtained under our present experimental condition. It is shown that combining WVA technique and BHD can strengthen each other's advantages and can behave better for some special application scenarios, such as extremely weak output, wider measurement bandwidth, etc. Moreover, the precision can be further enhanced by experimental parameter optimization.