Highly sensitive self-calibrating birefringence measurement based on anisotropic laser feedback polarization effect

Abstract Accurate measurements of dual parameters of phase retardance and retardance axis of birefringent materials are of fundamental importance to their fabrication and applications. However, current techniques typically exhibit limited versatility, suffering from high complexity, insufficient accuracy, and low efficiency. In this study, we propose and demonstrate the anisotropic laser feedback polarization effect for birefringent measurement, featuring simultaneous dual-parameter demodulation, unified polarization modulation-analysis architecture, high detection sensitivity, user-friendly operation, and versatile functionality. Importantly, such system can be self-calibrated with its own physical phenomena to reduce the installation derivation. To showcase the powerful effectiveness, we perform the static birefringence, dynamic birefringence variation, and spatial birefringence distribution, which remarkably exhibits the standard deviation of 0.0453° and 0.0939° for phase retardance and retardance axis azimuth, with the limit allowable sample transmittance around 10 –5 . This work demonstrates comprehensive applicability across diverse birefringence scenarios, extending the application of anisotropic laser feedback polarization effect, while establishing a novel strategy for birefringence measurement.