Self-calibrated Fourier transform spectrometer for laser-induced fluorescence spectroscopy with single-photon avalanche diode detection.

Abstract

Fourier transform spectrometers are commonly used in scientific and industrial settings because of their ability to record complete spectra with high signal-to-noise ratios. Using a single-photon avalanche diode as the detector improves the sensitivity but adds complications in laser-induced fluorescence applications related to detector saturation and acquisition time exceeding the typical scan time. Here, we report a spectrometer for the detection of laser-induced fluorescence signal together with the excitation light, and use the second harmonic signal from the excitation light to correct the phase and calibrate the spectrum, removing the need for a separate calibration source. We achieve a resolution of 0.4cm-1 in the wavelength range of 1140.2 nm, and demonstrate detection of signals with powers as low as 377fW, with a noise floor of 172fW/cm-1.