Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE

Heterodyne interferometry at the single-photon level

Parameswaran Hariharan, Nicholas Brown, Ichiro Fujima, Barry C. Sanders

Published Jun 14, 1995• 0 citations
Publisher

Abstract

Heterodyne interferometry uses beats produced by superposing two light waves with different frequencies at a photodetector. The output from the photodetector then contains a component at the beat frequency which can be processed to obtain information on changes in the optical path difference. We present experimental results which show that beats can be observed down to power levels at which the mean time interval between the arrival of photons at the photodetector is much greater than the transit time from the laser source to the detector and also when the mean time interval between photons is greater than the period of the beat. These results show that the beats are not due to the interference of one photon with another, but arise from a succession of single-photon events. It follows that measurements can be made even at extremely low photon fluxes by using homodyne detection and extending the integration time.

DOI
10.1117/12.211859

Related papers

Single-photon optical heterodyning

C.C. Davis

Optical heterodyning has been observed at the single-photon level by recording the sinusoidal variation in the probability for detection of a photoelectron from a photomultiplier tube illuminated with a FM laser and a local oscillator laser. The single-photon character of the heterodyne process was demonstrated by observation of beat signals at total power levels down to6 \times 10^{-15}W where the spacing between photons emitted from the source laser was\sim40 000times greater than their transit time through the apparatus.

IEEE Journal of Quantum Electronics•Jan 1, 1979•14 citations

Ultra-high-frequency Beats Produced by Laser Modes at the Single-photon Level

P. Hariharan, Ninita H. Brown, Ichiro Fujima +1 more

A helium-neon laser operating in two or more axial modes generates beat signals in the ultra-high frequency (UHF) range at a photodetector. An analysis of earlier data obtained at very low light levels shows that such UHF beats can be observed even when the mean time interval between the arrival of successive photons at the photodetector is greater than the period of the beat. This is because the beat is actually a sinusoidal modulation of a random carrier.

Journal of Modern Optics•Mar 1, 1995•4 citations

Photon heterodyning and its applications (Conference Presentation)

Youhei Okawa, Fuminori Omura, Yuhsuke Yasutake +1 more

Photon heterodyning affords the opportunity to single out photon detection events at a designated timing in the otherwise elusive transient interference fringes of single photons. Albeit essentially a time-domain analogue of Young's two-slit interference experiment at a single-photon level, it must be borne out by experiment using true single-photon streams. More importantly, it presents a technical challenge even without a tangible screen unlike space domain. Here, we demonstrate single-photon self-heterodyne beats that are obtained by letting the nonclassical light field associated with a photon interfere with itself. This is made possible by splitting, folding and mapping point-by-point the otherwise only poorly correlated time-series data onto a virtual capture frame. Photon heterodyning is of significance in view of conceivable applications. In fact, it marks a great step forward in benefiting such applications that handle interfering light fields in the time domain. An unmatched immunity to dc noise at an extremely low light level opens up the avenue for single-photon interferometry and interferometric biometrics of a highly light-sensitive target. Super-resolution and quantum optical coherence tomography, which are based on the nonclassical nature of photons, are those which should take full advantage of the photon heterodyning technology. On the other hand, the potential of photon heterodyning is most likely to be manifest in the field of quantum information processing by implementing frequency-encoded photon states. Some of these examples will be discussed in more detail.

Advanced Photon Counting Techniques•May 14, 2018•0 citations

Photon heterodyning

Youhei Okawa, Fuminori Omura, Yuhsuke Yasutake +1 more

Single-photon interference experiments are attempted in the time domain using true single-photon streams. Self-heterodyning beats are clearly observed by letting the field associated with a single photon interfere with itself on a field-quadratic detector, which is a time analogue of Young's two-slit interference experiment. The temporal first-order coherence of single-photon fields, i.e., transient interference fringes, develops as cumulative detection events are mapped point-by-point onto a virtual capture frame by properly correlating the time-series data. The ability to single out photon counts at a designated timing paves the way for digital heterodyning with faint light for such use as phase measurement and quantum information processing.

Optics Express•Aug 10, 2017•9 citations

Coherent lidar at low signal powers: Basic considerations on optical heterodyning

Peter J. Winzer, Walter R. Leeb

In a number of optical heterodyne systems it may happen that the signal power is so low that only a few, or even fractions of, photons enter the receiver in a characteristic time interval. As the heterodyne receiver basically employs the beating effect, such intricate questions as “is there still a beating between the (many) local oscillator photons and the few return photons?” or “how can a single photon produce an intermediate frequency?” arise. We show that the semiclassical theory, which provides exact results as long as optical fields with an adequate classical description are used, is capable of answering those questions. The term “photon” must thereby be assigned its (semiclassically) correct meaning, which is an abbreviation for “discrete interaction of light and matter.” We illustrate our discussion by providing a numerical example related to a space-borne CO2 Doppler wind lidar instrument.

Journal of Modern Optics•Aug 1, 1998•11 citations

Observation of spatial beating at near optical frequencies in the interference of two photons

Z. Y. Ou, L. Mandeļ

An experiment has been performed in which signal and idler photons produced in the process of parametric downconversion are mixed at a beam splitter, and the mixed beam splitter outputs are directed to two photodetectors feeding a coincidence counter. Two optical filters with passbands centered at frequencies ω1, and ω2 are inserted just before the detectors. When the two-photon coincidence rate is measured as a function of the time delay δτ introduced between the two photons, it is found that the rate exhibits a cosine variation with δτ at the difference frequency |ω1− ω2|. The experimental results are consistent with a quantum analysis of the experiment but not with a classical treatment. We have observed a beat note with a period of 37 fs, which is several orders of magnitude shorter than the resolving time of the photodetectors. In principle a beat note should be observable at optical frequencies with this technique.

Annual Meeting Optical Society of America•Jan 1, 1988•0 citations
Heterodyne interferometry uses beats produced by superposing two light waves with different frequencies at a photodetector. The output from the photodetector then contains a component at the beat frequency which can be processed to obtain information on changes in the optical path difference. We present experimental results which show that beats can be observed down to power levels at which the mean time interval between the arrival of photons at the photodetector is much greater than the transit time from the laser source to the detector and also when the mean time interval between photons is greater than the period of the beat. These results show that the beats are not due to the interference of one photon with another, but arise from a succession of single-photon events. It follows that measurements can be made even at extremely low photon fluxes by using homodyne detection and extending the integration time.
Optical heterodyning has been observed at the single-photon level by recording the sinusoidal variation in the probability for detection of a photoelectron from a photomultiplier tube illuminated with a FM laser and a local oscillator laser. The single-photon character of the heterodyne process was demonstrated by observation of beat signals at total power levels down to6 \times 10^{-15}W where the spacing between photons emitted from the source laser was\sim40 000times greater than their transit time through the apparatus.
Photon heterodyning affords the opportunity to single out photon detection events at a designated timing in the otherwise elusive transient interference fringes of single photons. Albeit essentially a time-domain analogue of Young's two-slit interference experiment at a single-photon level, it must be borne out by experiment using true single-photon streams. More importantly, it presents a technical challenge even without a tangible screen unlike space domain. Here, we demonstrate single-photon self-heterodyne beats that are obtained by letting the nonclassical light field associated with a photon interfere with itself. This is made possible by splitting, folding and mapping point-by-point the otherwise only poorly correlated time-series data onto a virtual capture frame. Photon heterodyning is of significance in view of conceivable applications. In fact, it marks a great step forward in benefiting such applications that handle interfering light fields in the time domain. An unmatched immunity to dc noise at an extremely low light level opens up the avenue for single-photon interferometry and interferometric biometrics of a highly light-sensitive target. Super-resolution and quantum optical coherence tomography, which are based on the nonclassical nature of photons, are those which should take full advantage of the photon heterodyning technology. On the other hand, the potential of photon heterodyning is most likely to be manifest in the field of quantum information processing by implementing frequency-encoded photon states. Some of these examples will be discussed in more detail.
Single-photon interference experiments are attempted in the time domain using true single-photon streams. Self-heterodyning beats are clearly observed by letting the field associated with a single photon interfere with itself on a field-quadratic detector, which is a time analogue of Young's two-slit interference experiment. The temporal first-order coherence of single-photon fields, i.e., transient interference fringes, develops as cumulative detection events are mapped point-by-point onto a virtual capture frame by properly correlating the time-series data. The ability to single out photon counts at a designated timing paves the way for digital heterodyning with faint light for such use as phase measurement and quantum information processing.
In a number of optical heterodyne systems it may happen that the signal power is so low that only a few, or even fractions of, photons enter the receiver in a characteristic time interval. As the heterodyne receiver basically employs the beating effect, such intricate questions as “is there still a beating between the (many) local oscillator photons and the few return photons?” or “how can a single photon produce an intermediate frequency?” arise. We show that the semiclassical theory, which provides exact results as long as optical fields with an adequate classical description are used, is capable of answering those questions. The term “photon” must thereby be assigned its (semiclassically) correct meaning, which is an abbreviation for “discrete interaction of light and matter.” We illustrate our discussion by providing a numerical example related to a space-borne CO2 Doppler wind lidar instrument.
An experiment has been performed in which signal and idler photons produced in the process of parametric downconversion are mixed at a beam splitter, and the mixed beam splitter outputs are directed to two photodetectors feeding a coincidence counter. Two optical filters with passbands centered at frequencies ω1, and ω2 are inserted just before the detectors. When the two-photon coincidence rate is measured as a function of the time delay δτ introduced between the two photons, it is found that the rate exhibits a cosine variation with δτ at the difference frequency |ω1− ω2|. The experimental results are consistent with a quantum analysis of the experiment but not with a classical treatment. We have observed a beat note with a period of 37 fs, which is several orders of magnitude shorter than the resolving time of the photodetectors. In principle a beat note should be observable at optical frequencies with this technique.