Approaching the Quantum Noise Limit of Heterodyne between a Continuous Wave Laser and an Optical Frequency Comb

Eugene Tsao, Noah Lordi, Alexander J. Lind, Matthew Heyrich, Josh Combes, Scott A. Diddams

Published Jan 1, 2023• 0 citations

Abstract

Frequency comb heterodyne underlies the highest precision measurements of frequency and time. While shot noise is typically considered the standard quantum limit,here we state where a new lower limit lies and show progress reaching this limit.

DOI: 10.1364/cleo_si.2023.sm2k.6

Related papers

Defining the Standard Quantum Limit of Heterodyne between a Continuous Wave Laser and an Optical Frequency Comb

Eugene Tsao, Noah Lordi, Alexander J. Lind +3 more

Optical clocks employ heterodyne between a laser and a frequency comb, yet the quantum description of this measurement is unknown. We define measurement operators and the standard quantum limit, and demonstrate progress reaching this limit.

Quantum 2.0 Conference and ExhibitionJan 1, 20230 citations

Ultimate Quantum Noise Limit of Frequency Comb Measurements

Ruoyu Liao, Youjian Song, Günter Steinmeyer

Frequency comb measurements have enormously progressed in the last decade, with 10-18precisions coming into reach [1]. Similar to Moore's law, the precision in frequency metrology measurements has improved by about 3 orders of magnitude in a little bit more than a decade. Along these lines, the question may arise whether there will be continuous improvements for decades to come - or whether, at one point, an ultimate limitation to further improvement arises. Moreover, frequency metrology has proven superior to other methods to evince a drift of fundamental physical constants, e.g., the fine-structure constants, yet no such drift has ever been convincingly proven using either optical [2] or cosmological methods [3]. So the question is: how low can we go before quantum effects impose an ultimate limit for precision frequency metrology?

Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC)Jun 1, 20190 citations

Continuum-field quantum optics of frequency comb metrology

Dong-Chel Shin, Edwin Ng, Myoung-Gyun Suh +1 more

Frequency combs enable precision measurements across timekeeping, spectroscopy, ranging and astronomy, and are now extending to integrated and field-deployable platforms. Realizing their full performance demands a comprehensive account of the quantum noise that arises when broadband optical fields are converted into finite-bandwidth electrical signals. Here we present a rigorous first-principles quantum-mechanical framework for optical frequency-comb metrology based on continuous-mode field quantization and a comb-line-resolved description of quantum fluctuations. The theory describes how quantum fluctuations of the comb field are transduced into electrical measurement noise. Formulated at the level of the comb field, the framework unifies the standard quantum limits of optical frequency division (OFD) and dual-comb spectroscopy (DCS) within a single treatment, and provides a general recipe for other comb-based measurements. On this footing, we identify practical, resource-efficient routes to quantum enhancement through engineered comb states, laying a foundation for the design of next-generation frequency combs operating at and beyond standard quantum limits.

quant-pharXiv:2605.16702May 19, 20260 citations

Subhertz interferometry at the quantum noise limit

Peng Yang, Boya Xie, Sheng Feng

Quantum noise limited interferometry for subhertz phase measurement is of essence in precision metrology applications, such as gravitational wave detection. However, suppression of subhertz classical noises below the shot-noise level is very challenging in practice. Two-frequency interferometry has been previously proposed to avoid low-frequency noises and may be useful for squeezing-enhanced high-precision phase measurement. Here we experimentally demonstrate a subhertz interferometer at the standard quantum noise (shot-noise) limit, by use of dual-frequency coherent probe light at the input and phase-sensitive heterodyne detection to measure the output interfered light. When the interferometer is locked at a dark fringe, the noise floor of the phase variance in the interferometer reaches the shot-noise level down to Fourier frequencies below 1 Hz. This work should pave a way for a realization of subhertz interferometry beyond the shot-noise limit.

Optics LettersApr 29, 201912 citations

High Frequency Optical Heterodyne Spectroscopy

M. Ducloy, J. J. Snyder

The progress over the last few years in the field of sub-Doppler saturated absorption spectroscopy has been greatly assisted by the development of new techniques for increasing sensitivity1-5. For many laboratory situations it is now routinely possible to achieve signal-to-noise ratios and sensitivities very near the quantum limit imposed by the fundamental statistical fluctuations (shot noise) of the probe laser beam.

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIEOct 19, 19831 citation

An optical innovation for metrology at the quantum limit of precision

Frequency-comb lasers are measuring sticks of the optical world and are used in metrology and sensing applications owing to their rigid, comb-like light spectra and metronomic pulsed output. A frequency comb with time-programmable pulses breaks this rigid mould and, in a demonstration of its utility, measures distances at the quantum limit of precision. A frequency-comb laser can be programmed to change pulse timing with high precision, to improve the sensitivity of distance measurements.

NatureOct 17, 20220 citations