Quantum Enhanced Measurement of an Optical Frequency Comb

TL;DR

This paper demonstrates quantum-enhanced multiparameter measurement of an optical frequency comb, surpassing the standard quantum limit using multimode quantum resources and multi-pixel spectral detection.

Contribution

It introduces a novel quantum metrology approach for simultaneous spectral parameter estimation with enhanced precision using multimode squeezed states.

Findings

Mean energy and central frequency measured with 19% and 15% noise reduction.

Surpassed shot-noise limit in multiparameter estimation.

Applicable to ultrafast quantum metrology and multimode quantum information.

Abstract

Measuring the spectral properties of an optical frequency comb is among the most fundamental tasks of precision metrology. In contrast to general single-parameter measurement schemes, we demonstrate here single shot multiparameter estimation at and beyond the standard quantum limit. The mean energy and the central frequency of ultrafast pulses are simultaneously determined with a multi-pixel-spectrally-resolved (MPSR) apparatus, without changing the photonics architecture. Moreover, using a quantum frequency comb that consists of multiple squeezed states in a family of Hermite-Gaussian spectral/temporal modes, the signal-to-noise ratios of the mean energy and the central frequency measurements surpass the shot-noise limit by around 19% and 15%, respectively. Combining our multi-pixel detection scheme and the intrinsic multimode quantum resource could find applications in ultrafast quantum metrology and multimode quantum information processing.