Photon Counting Detectors

Complete confocal fluorescence microscope that empowers researchers to advance quantitative functional imaging from individual molecules to cells and tissues.

Modular, customizable, time-resolved confocal microscope with single-molecule sensitivity for life and materials science.

Compact FLIM and FCS upgrade kit that adds advanced functional imaging and correlation analysis to existing laser scanning microscopes.

Designed for flexible, sensitive, and precise steady-state and time-resolved spectroscopy across the UV to NIR range and time scales from picoseconds to milliseconds.

Modular lifetime spectrometer designed for flexible fluorescence and photoluminescence measurements in both materials and life science research.

Add spectral and time-resolved photoluminescence to your setup through flexible microscope–spectrometer coupling options.

Get the most out of superconducting nanowire detectors in large-scale quantum communication and computing experiments requiring precise multichannel timing.

Boost your time-resolved experiments with a flexible, high-precision time tagging and TCSPC unit for materials science and quantum sensing.

Scale your photonic quantum computing and detector characterization setups while maintaining performance, flexibility, and high data throughput.

Compact 3-color picosecond laser delivering flexible ns to ms excitation with cost-effective multicolor performance and straightforward operation.

Smart picosecond laser diode heads covering UV-A to NIR, providing the right combination of power, pulse width, and diode type for any time-resolved technique.

VisUV provides clean short pulses and stable timing across key UV and visible wavelengths, including deep UV lines as well as 488 nm and 532 nm.

Enhance your single-photon counting experiments with wide dynamic range and excellent timing precision in the UV and visible even at the highest count rates.

Capture even the weakest signals over large areas with maximum dynamic range and enhanced low-light sensitivity in a compact detector design.

Unlock spatially resolved single-photon detection with a 23-pixel SPAD array, combining low dark counts and precise time tagging for advanced experiments.

Advanced FLIM analysis software for fast, accurate interpretation of lifetime imaging data.

Intuitive, free software solution for real-time, high-precision photon data acquisition, visualization, and initial data analysis.

Advanced software for time-resolved fluorescence acquisition and analysis.

An imaging technique that uses fluorescence lifetimes to generate image contrast.

Investigating how proteins dynamically explore multiple conformational states that control biological function.

Investigating how biomolecules separate into dynamic liquid phases to organize cellular space and regulate biological function.

A time-resolved technique that measures photoluminescence lifetimes to reveal excited-state dynamics in materials.

Studying exciton dynamics, charge carrier processes, and structural properties through optical and time-resolved characterization methods.

Investigating charge-carrier lifetimes and recombination dynamics to enable precise optical characterization of material quality and device performance.

A quantum optical signature revealed by time-resolved photon correlation analysis to identify single-photon emission in materials and nanostructures.

The transmission of information using individual photons, using quantum effects to ensure absolute security.

Quantifying photons per detection event enables direct access to photon-number statistics, providing insight into quantum and statistical properties of light.

An optical technique that analyzes light emission under electrical excitation to reveal electronic properties of electroluminescent materials.

Monitoring environmental signals and trace compounds to understand dynamic changes in natural and engineered environments.

A photon timing technique that measures single-photon arrival times to resolve ultrafast dynamics in fluorescence, materials research, and quantum optics.
Antibunching describes a non-classical property of light where photons are emitted one at a time rather than in groups. It is characterized by a reduced probability of detecting two photons simultaneously, typically expressed by the second-order correlation function indicating g²(0) < 1. Antibunching is a defining signature of single-photon emission and cannot be explained by classical light models. It is commonly observed in quantum emitters such as single molecules, quantum dots, color centers, or defects in solids, and plays a central role in quantum information processing and material characterization.
Scheme illustrating the setup and principle of antibunching measurements. Photon arrival times are recorded on two detection channels and correlated to obtain the second-order correlation function g²(τ), revealing the characteristic antibunching dip at zero lag time.Antibunching measurements are performed using time-resolved photon correlation techniques. Emitted photons are split into two detection paths and usually recorded with single-photon detectors in a Hanbury Brown and Twiss (HBT) configuration. By correlating photon arrival times, the second-order intensity correlation function g²(τ) is calculated. A pronounced dip at zero time delay indicates suppressed simultaneous emission and thus antibunching. Time-correlated single-photon counting (TCSPC) enables picosecond resolution, allowing antibunching to be resolved even for fast emitters and high repetition-rate excitation.

Antibunching data are typically represented as a second-order correlation histogram g²(τ), showing coincidence counts as a function of time delay following a multi-start multi-stop principle. Quantitative analysis focuses on the value of g²(0), which indicates the degree of single-photon purity, as well as on the shape of the correlation curve. Background correction, detector timing jitter, and afterpulsing effects must be accounted for to avoid false antibunching signatures. Fitting models may include lifetime information, multi-level emitter dynamics or bunching contributions at longer delays, providing insight into emitter kinetics, population dynamics, and environmental interactions.
PicoQuant software supports flexible coincidence correlation analysis via UniHarp and snAPI as well as quantitative evaluation of g²(τ) data for antibunching studies via QuCoa.
Antibunching measurements provide a direct and unambiguous test for single-photon emission. They are essential for identifying and validating quantum emitters, assessing photon purity, and distinguishing quantum light sources from classical or multi-emitter systems. In materials science, antibunching enables the study of defects, nanostructures, and low-dimensional materials at the single-emitter level. In quantum optics, it is fundamental to applications in quantum communication, quantum computing, and photon source characterization, even stretching towards novel imaging and microscopy techniques.
Instrumentation suited for antibunching measurements, including PMA Hybrid Series, PDM Series and PicoHarp 330.Reliable antibunching measurements require fast single-photon detectors with low timing jitter, low dark counts, and minimal afterpulsing. Time tagging electronics with high temporal resolution are essential for accurate correlation analysis. Stable pulsed or continuous-wave excitation sources are needed, depending on the emitter dynamics and excitation scheme. Multi-channel data throughput and precise timing synchronization are critical, especially at high count rates. Dedicated acquisition and analysis software is required to compute correlation functions, apply corrections, and extract quantitative g² values.
The following examples illustrate how antibunching measurements are applied to verify single-photon emission from solid-state quantum emitters and individual fluorescent molecules under controlled experimental conditions.

Nitrogen vacancy centers in diamond are well-established solid-state single-photon emitters with exceptional photostability and biocompatibility. Using the MicroTime 200 with 532 nm excitation and detection between 600–800 nm, FLIM imaging confirmed stable emission from sub-10 nm nanocrystals. Subsequent antibunching measurements revealed a pronounced g²(0) dip, demonstrating single-emitter behavior and validating their suitability for quantum optics, nanophotonics, and bioimaging applications.

Antibunching measurements of a highly diluted Atto 655 solution (0.1 nM) were performed using the MicroTime 200 with pulsed excitation at 635 nm. Detection in a standard Hanbury Brown and Twiss configuration and TCSPC analysis revealed a reduced correlation peak around 95 ns, confirming single-molecule emission behavior.

A time-resolved photon correlation technique that analyzes coincidence events between detection channels to quantify photon statistics. Antibunching measurements represent a specific application of coincidence correlation focused on identifying non-classical light emission.
Poster on high-spatial photoluminescence studies of nanostructures and quantum emitters using time-resolved confocal microscopy and spectroscopy.
Poster on next-generation TCSPC detection using PMA Hybrid detectors, enabling artifact-free FCS, antibunching measurements, and high-sensitivity FLIM imaging.
Please fill out the form below to receive the requested file. After submitting your details, the file will be sent to you by email.
* Required
Please fill out the form below to request more information. You may also use it to inquire about pricing, availability, technical specifications, or discuss your specific application. Our sales team will be happy to review your request and get in touch with you. If additional information is needed to process your inquiry, we will let you know.
* Required
Please fill out the form below to request more information about our products and services. You may also use it to ask for pricing, availability, technical specifications, or any other details relevant to your inquiry. Our team will be happy to review your request and get in touch with you. If additional information is needed to process your inquiry, we will let you know.
* Required
Please fill out the form below to request more information and prices about our product. Our team will be happy to review your request and get in touch with you. If additional information is needed to process your inquiry, we will let you know.
* Required