EAGER: Fundamental Considerations in Using Non-Hermitian Microscale Resonant Optical Structures for Rotation Sensing

University Of Southern California, Los Angeles CA

Investigators

Abstract

Measuring rotation rate is of utmost importance in a number of existing and emerging areas of science and technology, from general relativity, to robotics, medical-imaging, virtual reality, computer games, unmanned aerial vehicles (drones), and driverless cars. Over the years, various physical phenomena have been utilized for measuring rotation rates. In optics, the Sagnac effect has been employed to develop some of the finest and most accurate tools for determining rotational speeds. In fact, as of now, free-space ring laser gyroscopes (RLG) and passive fiber optic gyroscopes are among the most sensitive rotational sensors built to date. However, despite their superior performance in terms of resilience to shock and vibration, ring laser gyroscopes are not readily scalable and therefore cannot be integrated on chip. Recently, a technique based on differential gain architecture was proposed to significantly increase the sensitivity of RLGs. The goal of the proposed effort is to investigate the fundamental limitations of this technique and to pave the way towards the development of ultrasensitive ring laser gyroscopes on chip. The project will provide scientific training for students. Recent studies suggest that non-Hermitian degeneracies can significantly enhance the sensitivity of photonic resonant structures. One area where such sensitivity enhancement can become very useful is in ring laser gyroscopes (RLGs). In standard optical gyroscopes, sensitivity increases with the square root of the enclosed area. This behavior results in a fundamental trade-off between size and sensitivity. However, the use of non-Hermitian degeneracies or exceptional points for sensitivity enhancement raises several fundamental questions in terms of quantum noise, detection limit, measurement stability, and signal to noise ratio. The proposal aims to address these issues in an analytical and conclusive way and to determine the performance metrics for non-Hermitian gyroscopes. In addition, the design and fabrication of some of the constituent parts of the gyroscope will be considered. The proposed research may not only impact the technology of chip-scale gyroscopes, but will also advance the science of non-Hermitian physics.