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

arXiv:2610.32885

Polarization-encoded photon statistics for counting dipole emitters

Oumeng Zhang

Published Oct 23, 2026• 0 citations
arXivHTMLPDF

Abstract

Counting the emitters within a diffraction-limited region is a prerequisite for localizing overlapping molecules. Under pulsed excitation, each molecule emits at most one photon per pulse, so photon-number-resolved detection can count emitters without resolving them. But the required number of pulses grows steeply with the emitter number. Here we show that polarization, conventionally used to measure the orientations of dipole emitters, also carries information on their number. Because mean polarization-resolved signals are unchanged when every emitter is replaced by multiple dimmer copies, this information resides in the photon statistics within each pulse, which polarization reshapes in two ways. Linearly polarized excitation at three angles increases the sub-Poissonian deficit of the photon count by a factor of 1.5 for any emitter orientation, and detection in four polarization channels reveals the emitter number through how the photons of multiphoton pulses are distributed among the channels. Maximum-likelihood simulations for two to five emitters of unknown orientations and brightnesses show that three-angle excitation reduces the required number of pulses by about 2.3-fold, close to the predicted $1.5^2=2.25$, and that adding four-channel detection raises the reduction to as much as 4.8-fold. These gains require only polarization optics added to photon-number-resolved detection.

DOI
10.48550/arxiv.2610.32885

Related papers

En route to nanoscopic quantum optical imaging: counting emitters with photon-number-resolving detectors

Shuo Li, Wenchao Li, Vladislav V. Yakovlev +2 more

The fundamental understanding of biological pathways requires minimally invasive nanoscopic optical resolution imaging. Many approaches to high-resolution imaging rely on localization of single emitters, such as fluorescent molecules or quantum dots. Additionally, the exact determination of the number of such emitters in an imaging volume is essential for a number of applications; however, in standard intensity-based microscopy it is not possible to determine the number of individual emitters within a diffraction limited spot without initial knowledge of system parameters. Here we explore how quantum measurements of the emitted photons using photon number resolving detectors can be used to address this challenging task. In the proposed new approach, the problem of counting emitters reduces to the task of determining differences between the emitted photon distribution and the Poisson limit. We show that quantum measurements of the number of photons emitted from an ensemble of emitters enable the determination of both the number of emitters and the probability of emission. This method can be applied for any type of single-photon emitters. The scaling laws of this new approach are presented by the Cramer-Rao Lower Bounds, and this technique has great potential in quantum optical imaging with nanoscopic resolution.

arXiv:2110.03893•Optics Express•Mar 21, 2022•7 citations

Photon statistics in single molecule orientational imaging

Matthew R. Foreman, Sherif S. Sherif, Péter Török

Optical techniques in single molecule imaging rely heavily on photon counting for data acquisition. Extraction of information from the recorded readings is often done by means of statistical signal processing, however this requires a full knowledge of the photoelectron statistics. In addition to counting statistics we include a specific form of random signal variations namely reorientational dynamics, or wobble to derive the general probability density function of the number of detected photons. The relative importance of the two factors is dependent upon the total number of photons in the system and results are given in all regimes.

Optics Express•Jan 1, 2007•11 citations

Polarization Dynamics of Solid-State Quantum Emitters

Anand Kumar, Çağlar Samaner, Chanaprom Cholsuk +10 more

Quantum emitters in solid-state crystals have recently attracted a lot of attention due to their simple applicability in optical quantum technologies. The polarization of single photons generated by quantum emitters is one of the key parameters that play a crucial role in the applications, such as quantum computation that uses the indistinguishability of photons. However, the degree of single photon polarization is typically quantified using time-averaged photoluminescence intensity of single emitters, which provides limited information about the dipole properties in solids. In this work, we use single defects in hexagonal boron nitride and nanodiamond as efficient room-temperature single photon sources to reveal the origin and the temporal evolution of dipole orientation in solid-state quantum emitters. The angle of excitation and emission dipoles relative to the crystal axes are determined experimentally and then calculated using density functional theory, which results in characteristic angles for every specific defect that can be used as an efficient tool for defect identification and understanding their atomic structure. Moreover, the temporal polarization dynamics reveal a strongly modified linear polarization visibility that depends on the excited state decay time of individual excitation. This effect can be traced back potentially to the excitation of excess charges in the local crystal environment. Understanding such hidden time-dependent mechanisms can further be used to improve the performance of polarization-sensitive experiments, in particular that of quantum communication with single photon emitters.

arXiv:2303.04732•Mar 8, 2023•4 citations

Polarization Dynamics of Solid-State Quantum Emitters

Anand Kumar, Çağlar Samaner, Chanaprom Cholsuk +10 more

Quantum emitters in solid-state crystals have recently attracted a great deal of attention due to their simple applicability in optical quantum technologies. The polarization of single photons generated by quantum emitters is one of the key parameters that plays a crucial role in various applications, such as quantum computation, which uses the indistinguishability of photons. However, the degree of single-photon polarization is typically quantified using the time-averaged photoluminescence intensity of single emitters, which provides limited information about the dipole properties in solids. In this work, we use single defects in hexagonal boron nitride and nanodiamond as efficient room-temperature single-photon sources to reveal the origin and temporal evolution of the dipole orientation in solid-state quantum emitters. The angles of the excitation and emission dipoles relative to the crystal axes were determined experimentally and then calculated using density functional theory, which resulted in characteristic angles for every specific defect that can be used as an efficient tool for defect identification and understanding their atomic structure. Moreover, the temporal polarization dynamics revealed a strongly modified linear polarization visibility that depends on the excited-state decay time of the individual excitation. This effect can potentially be traced back to the excitation of excess charges in the local crystal environment. Understanding such hidden time-dependent mechanisms can further improve the performance of polarization-sensitive experiments, particularly that for quantum communication with single-photon emitters.

ACS Nano•Feb 9, 2024•24 citations

Experimental approach to extend the range for counting fluorescent molecules based on photon-antibunching

Haisen Ta, Alexander Kiel, Michael Wahl +1 more

In single-molecule fluorescence spectroscopy photon-antibunching is frequently used to prove the occurrence of single fluorophores. Furthermore, the relative frequency of coincident photon pairs was also used to determine the number of fluorophores in the diffraction limited observation volume of a confocal microscope. However, the ability to count fluorophores is so far limited to approximately 3 molecules due to saturation of the calibration curve with increasing number of fluorophores. Recently, we introduced a novel theoretical framework for counting the number of emitting molecules by analyzing photon-distributions acquired with a confocal microscope using four single-photon detectors. Here, we present the experimental realization of the proposed scheme in a confocal setup using novel multi-channel photon-counting electronics and DNA constructs that were labelled with five fluorophores. Our experimental results give a clear correlation between the number of estimated fluorophores and the number of bleaching steps for DNA probes conjugated with five ATTO647N labels with an error of approximately 20%. Moreover, we could acquire experimental data for up to 15 fluorophores indicating the simultaneous occurrence of three DNA probes. Our experiments put into perspective that the analysis of photon-distributions acquired with four detection channels is suited to count the number of fluorescently labelled molecules in larger aggregates or clusters with potential for applications in molecular and cell biology and for time-resolved analysis of multi-chromophoric compounds in material sciences.

Physical Chemistry Chemical Physics•Jan 1, 2010•43 citations

Fluorescence Quantification by Photon Statistics: From Objective Characterization to Application

Kristin S. Grußmayer

Quantitative information is key to unravel molecular processes in all fields of research. Counting by Photon Statistics (CoPS) is a single molecule technique that provides such quantification for fluorescent species. CoPS exploits the photon antibunching effect to infer \nthe number of independent emitters and their molecular brightness from multiple photon detection events. I laid the foundation for high quality results by improving the microscope detection efficiency more than threefold compared to earlier measurements. Using both simulations \nand experiments with defined, DNA-based probes, I investigated the critical interplay of fluorophore properties and analysis parameters. I discovered that measurements at high molecular brightness can be ten times faster than previously established which opens new possibilities for time resolved quantification. The findings stress that the choice of analysis parameters is vital and provide an objective measure of fluorophore eligibility for CoPS. I characterized sixteen \norganic dyes across the visible spectrum based on their molecular brightness and photostability. This study accomplished the transition of CoPS from a proof of concept technique to a widely applicable quantification method. Experiments demonstrated that CoPS can reveal \nthe label number distribution of fluorescent markers, a prerequisite for quantitative investigations in biology. Moreover, I showed that CoPS offers new perspectives for characterization of photophysical processes in photoluminescent materials.

•Jan 1, 2016•0 citations
Counting the emitters within a diffraction-limited region is a prerequisite for localizing overlapping molecules. Under pulsed excitation, each molecule emits at most one photon per pulse, so photon-number-resolved detection can count emitters without resolving them. But the required number of pulses grows steeply with the emitter number. Here we show that polarization, conventionally used to measure the orientations of dipole emitters, also carries information on their number. Because mean polarization-resolved signals are unchanged when every emitter is replaced by multiple dimmer copies, this information resides in the photon statistics within each pulse, which polarization reshapes in two ways. Linearly polarized excitation at three angles increases the sub-Poissonian deficit of the photon count by a factor of 1.5 for any emitter orientation, and detection in four polarization channels reveals the emitter number through how the photons of multiphoton pulses are distributed among the channels. Maximum-likelihood simulations for two to five emitters of unknown orientations and brightnesses show that three-angle excitation reduces the required number of pulses by about 2.3-fold, close to the predicted 1.52=2.251.5^2=2.251.52=2.25, and that adding four-channel detection raises the reduction to as much as 4.8-fold. These gains require only polarization optics added to photon-number-resolved detection.
The fundamental understanding of biological pathways requires minimally invasive nanoscopic optical resolution imaging. Many approaches to high-resolution imaging rely on localization of single emitters, such as fluorescent molecules or quantum dots. Additionally, the exact determination of the number of such emitters in an imaging volume is essential for a number of applications; however, in standard intensity-based microscopy it is not possible to determine the number of individual emitters within a diffraction limited spot without initial knowledge of system parameters. Here we explore how quantum measurements of the emitted photons using photon number resolving detectors can be used to address this challenging task. In the proposed new approach, the problem of counting emitters reduces to the task of determining differences between the emitted photon distribution and the Poisson limit. We show that quantum measurements of the number of photons emitted from an ensemble of emitters enable the determination of both the number of emitters and the probability of emission. This method can be applied for any type of single-photon emitters. The scaling laws of this new approach are presented by the Cramer-Rao Lower Bounds, and this technique has great potential in quantum optical imaging with nanoscopic resolution.
Optical techniques in single molecule imaging rely heavily on photon counting for data acquisition. Extraction of information from the recorded readings is often done by means of statistical signal processing, however this requires a full knowledge of the photoelectron statistics. In addition to counting statistics we include a specific form of random signal variations namely reorientational dynamics, or wobble to derive the general probability density function of the number of detected photons. The relative importance of the two factors is dependent upon the total number of photons in the system and results are given in all regimes.
Quantum emitters in solid-state crystals have recently attracted a lot of attention due to their simple applicability in optical quantum technologies. The polarization of single photons generated by quantum emitters is one of the key parameters that play a crucial role in the applications, such as quantum computation that uses the indistinguishability of photons. However, the degree of single photon polarization is typically quantified using time-averaged photoluminescence intensity of single emitters, which provides limited information about the dipole properties in solids. In this work, we use single defects in hexagonal boron nitride and nanodiamond as efficient room-temperature single photon sources to reveal the origin and the temporal evolution of dipole orientation in solid-state quantum emitters. The angle of excitation and emission dipoles relative to the crystal axes are determined experimentally and then calculated using density functional theory, which results in characteristic angles for every specific defect that can be used as an efficient tool for defect identification and understanding their atomic structure. Moreover, the temporal polarization dynamics reveal a strongly modified linear polarization visibility that depends on the excited state decay time of individual excitation. This effect can be traced back potentially to the excitation of excess charges in the local crystal environment. Understanding such hidden time-dependent mechanisms can further be used to improve the performance of polarization-sensitive experiments, in particular that of quantum communication with single photon emitters.
Quantum emitters in solid-state crystals have recently attracted a great deal of attention due to their simple applicability in optical quantum technologies. The polarization of single photons generated by quantum emitters is one of the key parameters that plays a crucial role in various applications, such as quantum computation, which uses the indistinguishability of photons. However, the degree of single-photon polarization is typically quantified using the time-averaged photoluminescence intensity of single emitters, which provides limited information about the dipole properties in solids. In this work, we use single defects in hexagonal boron nitride and nanodiamond as efficient room-temperature single-photon sources to reveal the origin and temporal evolution of the dipole orientation in solid-state quantum emitters. The angles of the excitation and emission dipoles relative to the crystal axes were determined experimentally and then calculated using density functional theory, which resulted in characteristic angles for every specific defect that can be used as an efficient tool for defect identification and understanding their atomic structure. Moreover, the temporal polarization dynamics revealed a strongly modified linear polarization visibility that depends on the excited-state decay time of the individual excitation. This effect can potentially be traced back to the excitation of excess charges in the local crystal environment. Understanding such hidden time-dependent mechanisms can further improve the performance of polarization-sensitive experiments, particularly that for quantum communication with single-photon emitters.
In single-molecule fluorescence spectroscopy photon-antibunching is frequently used to prove the occurrence of single fluorophores. Furthermore, the relative frequency of coincident photon pairs was also used to determine the number of fluorophores in the diffraction limited observation volume of a confocal microscope. However, the ability to count fluorophores is so far limited to approximately 3 molecules due to saturation of the calibration curve with increasing number of fluorophores. Recently, we introduced a novel theoretical framework for counting the number of emitting molecules by analyzing photon-distributions acquired with a confocal microscope using four single-photon detectors. Here, we present the experimental realization of the proposed scheme in a confocal setup using novel multi-channel photon-counting electronics and DNA constructs that were labelled with five fluorophores. Our experimental results give a clear correlation between the number of estimated fluorophores and the number of bleaching steps for DNA probes conjugated with five ATTO647N labels with an error of approximately 20%. Moreover, we could acquire experimental data for up to 15 fluorophores indicating the simultaneous occurrence of three DNA probes. Our experiments put into perspective that the analysis of photon-distributions acquired with four detection channels is suited to count the number of fluorescently labelled molecules in larger aggregates or clusters with potential for applications in molecular and cell biology and for time-resolved analysis of multi-chromophoric compounds in material sciences.
Quantitative information is key to unravel molecular processes in all fields of research. Counting by Photon Statistics (CoPS) is a single molecule technique that provides such quantification for fluorescent species. CoPS exploits the photon antibunching effect to infer \nthe number of independent emitters and their molecular brightness from multiple photon detection events. I laid the foundation for high quality results by improving the microscope detection efficiency more than threefold compared to earlier measurements. Using both simulations \nand experiments with defined, DNA-based probes, I investigated the critical interplay of fluorophore properties and analysis parameters. I discovered that measurements at high molecular brightness can be ten times faster than previously established which opens new possibilities for time resolved quantification. The findings stress that the choice of analysis parameters is vital and provide an objective measure of fluorophore eligibility for CoPS. I characterized sixteen \norganic dyes across the visible spectrum based on their molecular brightness and photostability. This study accomplished the transition of CoPS from a proof of concept technique to a widely applicable quantification method. Experiments demonstrated that CoPS can reveal \nthe label number distribution of fluorescent markers, a prerequisite for quantitative investigations in biology. Moreover, I showed that CoPS offers new perspectives for characterization of photophysical processes in photoluminescent materials.