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

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Fourier-transform hyperspectral imaging system

Hyperspectral imagingHyperspectral MicroscopyRemote sensingSpectroscopy

Introduction

Hyperspectral imaging is a technique which acquires the whole spectral information from each point of an image. Our innovation is a hyperspectral imaging device based on the concept of the Fourier transform spectroscopy and it employs a novel birefringent common-path interferometer. The device can work in the spectral range from the ultraviolet to the mid-infrared, and can be configured as a camera (e.g. for remote sensing) and as a microscope.

Technical features

The innovation of our device is the use of an ultrastable birefringent interferometer in the imaging system. In our apparatus, the light from the object of interest travels through the birefringent common-path interferometer, and is divided into two delayed collinear replicas. Their delay can be varied by the interferometer with robust, sub-optical cycle precision. For each delay, a two-dimensional detector acquires the interference pattern between them, which is then analyzed by taking the Fourier transform at each pixel of the bi-dimensional detector. Our scheme is characterized by exceptional long-time stability and sub-wavelength precision, thus enabling fast acquisition of spectral images with high frequency and space resolution. In addition, our birefringent device can be easily integrated both in remote-sensing cameras and in microscopes.

Possible Applications

  • Mining applications;
  • Analysis of pharmaceutical products;
  • Agriculture and analysis of forests;
  • Quality control of food;
  • Identification and sorting of materials;
  • Mapping of works of art;
  • Remote sensing;
  • Search of oil fields;
  • Analysis of blood and fingerprints.

Advantages

  • High optical throughput, enabling short acquisition times;
  • Adjustable spectral resolution;
  • Broad spectral range, from the UV to the IR;
  • The interferometer is more compact and stable than existing schemes;
  • More compact, portable, robust than existing interferometers;
  • Easy integration both in remote sensing cameras and in microscopes.