Mid-Infrared Quantum Imaging and Spectroscopy

• Applicant: Dr. Sven Ramelow
• Subject Area: Optics, Quantum Optics and Physics of Atoms, Molecules and Plasmas
• Term: from 2016 to 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 314745413

• Final Report Year: 2024

Final Report Abstract

The DFG project carried out pioneering experiments on infrared measurements with non-linear interferometers: By using entangled photon pairs, the illumination of the sample can be realized with MIR photons, but the sample properties can be determined exclusively by measuring the NIR photons entangled with the MIR photons - neither MIR detectors nor lasers are necessary in this technologically demanding spectral range, which is why the method is also called measurement with “undetected photons”. This has major technological advantages, as MIR sensing has so far been severely limited in its realworld application by high costs and long measurement times: Devices on the market (based on scanning FTIR spectroscopy or quantum cascade laser technology) are complex and cost-intensive and on the one hand often too slow to be suitable for routine use, e.g. in medical laboratories. The main reasons for this are the continuing high technological hurdles in both the generation and detection of MIR radiation, which are completely circumvented in the approach pursued here. The project initially discovered and patented a new way of generating very broadband photon pairs. This made it possible to conduct experiments on different measurement modalities: Firstly, high-resolution optical coherence tomography in the MIR with NIR grating spectrometers could be demonstrated, with a wide range of possible applications, e.g. in ceramic inspection. This is currently being further developed into a demonstrator in a BMBF-funded joint industrial project in order to validate the commercial usability of this method. Furthermore, this method could be used for MIR microscopy, where fundamental relationships between resolution and the number of imaged image elements could be derived. These were confirmed in demonstration experiments - with the first promising measurements on tissue samples from mouse hearts in collaboration with bio-medical researchers at the Max Delbrück Center, Berlin. In an application-oriented lighthouse BMBF project with industrial partners, the methodology is currently being further developed into a demonstrator for clinical application and cancer diagnostics. Finally, further experiments have demonstrated MIR spectroscopy with NIR grating spectrometers, a technique that has considerable advantages over methods using conventional light sources (speed, resolution, compactness, price) and could therefore replace them in applications such as microplastics analysis. A corresponding BMBF project is currently dedicated to the development of a demonstrator for this.

Publications

• Effects of time-energy correlation strength in molecular entangled photon spectroscopy. Physical Review A, 100(5).
  Lever, Fabiano; Ramelow, Sven & Gühr, Markus
  
• German patent DE102018206810B3, “Verfahren zum Herstellen eines Bauelements, Bauelement und Verwendung des Bauelements” - siehe “Ultra-broadband SPDC for spectrally far separated photon pairs” OL 44, 4638 (2019)

  Ramelow, Sven & Vanselow, Aron
  
• Ultra-broadband SPDC for spectrally far separated photon pairs. Optics Letters, 44(19), 4638.
  Vanselow, Aron; Kaufmann, Paul; Chrzanowski, Helen M. & Ramelow, Sven
  
• Frequency-domain optical coherence tomography with undetected mid-infrared photons. Optica, 7(12), 1729.
  Vanselow, Aron; Kaufmann, Paul; Zorin, Ivan; Heise, Bettina; Chrzanowski, Helen M. & Ramelow, Sven
  
• Microscopy with undetected photons in the mid-infrared. Science Advances, 6(42).
  Kviatkovsky, Inna; Chrzanowski, Helen M.; Avery, Ellen G.; Bartolomaeus, Hendrik & Ramelow, Sven
  
• Versatile Super-Sensitive Metrology Using Induced Coherence. Quantum, 5, 458.
  Miller, Nathaniel R.; Ramelow, Sven & Plick, William N.
  
• Mid-infrared microscopy via position correlations of undetected photons. Optics Express, 30(4), 5916.
  Kviatkovsky, Inna; Chrzanowski, Helen M. & Ramelow, Sven
  
• Mid-IR spectroscopy with NIR grating spectrometers. Optics Express, 30(4), 5926.
  Kaufmann, Paul; Chrzanowski, Helen M.; Vanselow, Aron & Ramelow, Sven
  
• Quantum imaging and metrology with undetected photons: tutorial. Journal of the Optical Society of America B, 39(8), 2200.
  Barreto, Lemos Gabriela; Lahiri, Mayukh; Ramelow, Sven; Lapkiewicz, Radek & Plick, William N.