Single-Pixel Fluorescence Spectroscopy Using Near-Field Dispersion for Single-Photon Counting and Single-Shot Acquisition

Abstract

Time-resolved sensing of fluorescence quanta provides exceptionally versatile information−including access to nanoscopic structure, chemical environment and nonclassical behavior of quantum emitters. Combined spectro-temporal information is typically obtained using spatial dispersion with photoelectron imaging such as streak-cameras or position-sensitive counting and, alternatively, sequential filtering with single-pixel detectors. However, such schemes require complex, expensive and low-sensitivity detectors or rely on scanning acquisition. Here, we demonstrate a single-pixel implementation of fluorescence emission spectroscopy entirely in the temporal domain compatible with (a) time-correlated single-photon counting (TCSPC) and (b) high-speed single-shot detection. Harnessing the near-field regime of the Time-Stretch Dispersive Fourier Transformation (TS-DFT), we encode spectral information via chromatic dispersion into temporal signals, and we demonstrate the retrieval of entwined information via a direct deconvolution using prior knowledge. Addressing high optical throughput for extended emitters, we introduce a high-bandwidth graded-index multimode fiber for TS-DFT. As proof-of-concept, we present rapid single-shot optical thermometry based on quantum-dot luminescence. Given its high speed, efficiency, and simplicity, we foresee broad applications for fast hyperspectral confocal fluorescence microscopy, low-light sensing, and highthroughput spectral screening.

Mid-infrared single-photon upconversion spectroscopy enabled by nonlocal wavelength-to-time mapping

“…In the frequency upconversion process, the quantum-correlated properties of MIR photons are well maintained. The conjugated NIR heralding photons from photon pairs are routed via a 10-km single-mode fiber (SMF) to acquire group velocity dispersion (GVD), enabling wavelength-to-time mapping (35)(36)(37)(38)(39). Because of the quantum correlation inherited by the upconverted photons, we successfully implement correlation measurement that nonlocally maps the spectral information contained by the MIR signal photons into the time domain.…”

Single‐Photon Time‐Stretch Infrared Spectroscopy

“…[29] Such time-stretch spectroscopy is initially devised to realize single-shot measurement for capturing non-repetitive or transient events, [28] which has now been extended to the single-photon regime by combining the time-correlated single photon counting (TCSPC) technique. For instance, the single-photon time-stretch concept has been adopted in photon-pair characterization, [30][31][32][33] photonic waveform reconstruction, [34] quantum microwave photonics, [35] single-pixel fluorescence analysis, [36] and lightweight Raman spectroscope. [37] However, all these demonstrations are restricted in the near-infrared region.…”

Single-Photon Level Dispersive Fourier Transform: Ultrasensitive Characterization of Noise-Driven Nonlinear Dynamics

“…Indeed, single-photon detectors (SPD) have followed tremendous technological improvements and can reach extremely low timing jitter (down to a few picoseconds) while ensuring excellent sensitivity (quantum efficiency over 90%) and low instrumental noise (50 photons/s). This technological progress was instrumental in the development of highly resolved quantum measurements in the temporal and spectral domains − but also proved extremely relevant for applications in coherent signal processing and imaging, , where quantum-inspired DFT measurements can play the role of ultrasensitive spectrometers . However, when it comes to real-time (or shot-to-shot) monitoring of incoherent spectral dynamics, the sparse detection and random sampling of (at best) one photon per DFT spectrum with a unique single-photon detector drastically hamper the statistical analysis of broadband spectral fluctuations.…”