TABLE 2 |.

Fluorescence lifetime measuring technology and methods in the past decade.

References	Technology and methods	Brief summary
Yuan et al. [70]	Fluorescence spectrometer, AOTF, optical biopsy	AOTF and collection of first-order diffraction beams. Acquisition of 200 nm time-resolved spectra in 4 s.
Houston et al. [39]	Frequency domain TRFC, lifetime-based sorting, ORCAS	Open reconfigurable cytometric acquisition system (ORCAS) adds capability to perform lifetime analysis on any cytometer with a laser that can be modulated.
Tyndall et al. [42]	TCSPC, SPAD Array, integrated silicon photomultiplier (SiPM)	Parallelization of TCSPC to overcome photon pile-up. CMOS process used to make a SiPM with SPAD array, TDCs, and lifetime estimation on-chip.
Li et al. [5]	fd-TRFC, fluorescence lifetime excitation cytometry by kinetic dithering (FLECKD)	Rapid scanning of laser across sample passing through flow cytometer. Able to discriminate multiple fluorescence lifetimes simultaneously.
Petersen et al. [6]	High throughput fluorescence lifetime plate reader. Direct waveform recording (DWR)	Waveforms are direclty digitized for lifetime calculation. Fluorescence lifetime plate reader can image 384-well microplate in 3 minutes with better than 1 % accuracy.
Nedbal et al. [2]	TCSPC, microfluidic FLIM, Burst-Integrated Fluorescence Lifetime (BIFL)	Epifluorescent microscope with associated BIFL software used to determine intensity of fluorescence, photon rate, lifetime, and burst duration for each cell.
Poland et al. [26]	Multifocal multiphoton FLIM (MM-FLIM), SPAD array, TCSPC, FRET	Parellelized MM-FLIM in both excitation and detection. Technique showed increased speed in comparison to confocal FLIM and widefield FLIM.
Rocca et al. [65]	TCSPC, CMOS SPAD array, SiPM, BIFL, Field Programmable gate arrays (FPGA)	A single-chip is equiped with SiPM capable of BIFL using TCSPC for detection and real-time sorting with FPGA using CMM for lifetime calcuation.
Lee et al. [15]	Phasor-FLIM based single cell screening	Single-cell traps within a microfluidic device allow for differentiation of cells based on metabolic differences in NAD(P)H without any labeling using phasor-FLIM
Mikami et al. [71]	Frequency-division multiplexing (FDM) confocal microscope, imaging flow cytometry	Integration of a dual-frequeny comb that was spatially distributed along with QAM into FDM. 16,000 frames/s surpassed the fluorescence lifetime limit
Schaaf et al. [32]	Red-shifted FRET biosensors (OFP and MFP), high throughput screening/plate reader	The FRET pair developed increased efficiency, dynamic range, and signal-to-background of HTS. Can image 1536 well-plate in 3 minutes
Shen et al. [17]	Custom continuous-flow bioreactor, real time two-photon FLIM (2P-FLIM)	2P-FLIM was implemented to continuously monitor live cultures under shear stress, eliminating traditional interuptions of the bioreactor
Esposito and Venkitaraman [10]	Hyperdimensional imaging microscopy (HDIM)	Parallel detection of orthogonal fluorescence characteristics (lifetime, polarization, and spectra). Hyperdimensional traits detected with two multiwavelength TCSPC detectors.
Yao et al. [24]	A deep convolution neural network (CNN) called Net-FLICS (FLIM with compressed sensing)	Reconstruction of intensity and FLI maps using deep learning. Reconstruction times of <3 ms/sample, 4 orders of magnitude faster than previous methodologies
Hirmiz et al. [33]	FLIM-FRET combined technology with a highly-multiplexed confocal microscope	Microscope was coupled to an SPAD array for high resolution and rapid imaging of FLIM
Karpf et al. [13]	Spectro-Temporal Laser Imaging by Difracted Excitation (SLIDE), imaging flow cytometry	Non-linear microscope with kHz frame rate using a pulse-modulated, sweeping laser with inertia-free steering. Lifetime recording of 88×106 pixels/s.