Ultra-sensitive tilt measurement based on exceptional point sensors with Hermite-Gaussian pointer

Abstract Parity-time (PT)-symmetric non-Hermitian systems exhibit a heightened sensitivity to external environmental changes, making them a popular choice in the field of quantum sensing. In this study, we designed a small tilt sensor based on the exceptional point (EP) of non-Hermitian systems. The measurement sensitivity of the sensor can be increased by a factor of 10000 times when compared with that of traditional sensors. However, in terms of the measurement precision of the EP sensor, there was no significant improvement because the EP sensor amplified the signal while amplifying the noise. Nonetheless, EP sensors retain clear advantages in specialized scenarios, such as detector saturation events, during which they surpass traditional sensors. Subsequently, we increased the measurement precision of the EP sensor by <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msqrt> <mml:mrow> <mml:mn>2</mml:mn> <mml:mi>n</mml:mi> <mml:mo>+</mml:mo> <mml:mn>1</mml:mn> </mml:mrow> </mml:msqrt> </mml:math> times by using high-order Hermite-Gaussian (HG) light, where <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mi>n</mml:mi> </mml:math> denotes the mode order of the signal light. Finally, we conclude this study with an analysis of the noise in EP sensors based on quantum error theory. Furthermore, we explore how EP sensors can strike a balance between high sensitivity and precision by incorporating a squeezed light field with elevated HG modes.