Toward an optical spectroscopy technique using photon absorption remote sensing

We present an optical spectroscopy system based on photon absorption remote sensing (PARS) that simultaneously captures radiative and non-radiative sample relaxation following UV-excitation. Non-radiative relaxations are measured through probing the excited sample’s thermal and pressure-induced refractive index changes, while a spectrometer is used to record radiative sample relaxation, which occurs as fluorescence. We benchmark the generated non-radiative, radiative, and combined total absorption PARS absorbance spectra of liquid eumelanin, NADH, DMSO, and methylene blue samples against data collected from UV–Visible spectrophotometry. Finally, we leverage the absorption and fluorescence spectral data collected from the PARS system to accurately determine the make-up of mixed craft ink samples. The PARS system overcomes the limitations of traditional optical spectroscopy techniques by broadening the range of samples that can be analyzed and by providing a more detailed level of sample characterization.