Politecnico di Torino - Corso Duca degli Abruzzi, 24 - 10129 Torino, ITALY

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BIRIFRANGENT INTERFEROMETER FOR MEASURING PHOTOLUMINESCENCE PROPERTIES

Excitation-Emission MatrixfluorescenceFluorescence spectroscopyTime-resolved Fluorescence

Introduction

This invention is a system to measure Excitation-Emission Matrix (EEM) maps of photoluminescent samples. It is based on Fourier Transform Spectroscopy (FTS) and it employs a common-path birefringent interferometer, with a  very high stability and reproducibility that leads to a working range from the Infrared to the ultraviolet spectral region. This device can be used also to measure time-resolved emission maps.

Technical features

The known techniques for making measurements of fluorescence (excitation) spectra show limitations in resolution, stability and light production capacity. This innovative device enhances the sensitivity, the resolution and shorten the acquisition time of EEM compared to currently commercially available devices. It enables one to measure fluorescence Excitation–Emission–Matrix (EEM) and, in parallel, absorption, fluorescence and fluorescence excitation spectra of samples over a broad bandwidth in a large spectral region. The EEM and the absorption spectra are retrieved by means of a Fourier transform of the interference signal between two replicas of the excitation light, whose relative delay is scanned by changing the insertion of a birefringent wedge. The common-path interferometer can be placed also in the detection beam path to spectrally resolve the emission of the sample and can be used in combination with a time-resolved detector to measure time-resolved emission maps.

Possible Applications

  • Biology;
  • Pharmaceutics;
  • Contaminant detection;
  • Quality control;
  • Research;
  • Food fraud detection.

Advantages

With respect to common devices:

  • More light reaches the detector leading to better sensitivity and lower acquisition time;
  • User adjustable spectral resolution without affecting light throughput;
  • The device is very simple and compact.