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Single Molecule Spectroscopy and Superresolution Imaging

Single photon spectroscopy combined with scanning confocal microscopy

Val Zwiller, Jessie Qin-Dregely

Published Mar 4, 2026• 0 citations
Publisher

Abstract

We present a new instrument; a quantum spectrometer able to time tag every detected photon making up a spectrum. The spectrometer can be coupled to a scanning confocal microscope to acquire spectra, lifetimes, photon correlations and cross-correlations in one single measurement. Our instrument offers higher detection efficiency and far lower noise levels than was previously available in the infrared.

DOI
10.1117/12.3089624

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We present a new instrument; a quantum spectrometer able to time tag every detected photon making up a spectrum. The spectrometer can be coupled to a scanning confocal microscope to acquire spectra, lifetimes, photon correlations and cross-correlations in one single measurement. Our instrument offers higher detection efficiency and far lower noise levels than was previously available in the infrared.
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Precisely timed detection of single photons plays an important role in the field of quantum information processing and fluorescence sensing. The method of time-correlated single photon counting is therefore constantly evolving and the associated instrumentation is being improved with new ideas and technologies. Simultaneous, time tagged readout of multiple detector channels is invaluable in many applications, spanning from fluorescence lifetime imaging in biology to the measurement of quantum optical correlations in basic research. Here we present a new integrated design, providing up to three independent input channels, a very short dead time, very high throughput, and a timing resolution of 25 ps at reasonable cost and small size. Apart from design features and test results of the instrument, we show an application in quantum optics, namely, the measurement of the photon statistics of a heralded single photon source based on cavity-enhanced spontaneous parametric down-conversion.
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Measurements of photon temporal correlations have been the mainstay of experiments in quantum optics. Over the past several decades, advancements in detector technologies have supported further extending photon correlation techniques to give rise to novel spectroscopy and imaging methods. This Perspective reviews the evolution of these techniques from temporal autocorrelations through multidimensional photon correlations to photon correlation imaging. State-of-the-art single-photon detector technologies are discussed, highlighting the main challenges and the unique current perspective of photon correlations to usher in a new generation of spectroscopy and imaging modalities.