145 144 Principal Scientist Profiles Frank Setzpfandt Frank Setzpfandt Principal Scientist Profiles RESEARCH GROUP LEADER QUANTUM OPTICS Since 2016, Dr. Setzpfandt leads a Research Group focused on quantum optics, especially targeting quantum imaging and sensing approaches as well as integrated quantum optics. Before, he was a PostDoc at the Institute of Applied Physics of the Friedrich Schiller University and the Nonlinear Physics Centre of the National University Canberra, Australia. He currently serves as CEO of the Thuringian Innovation Center for Quantum Optics and Sensors. FRANK SETZPFANDT RESEARCH AREAS The research of Dr. Setzpfandt focuses on the generation of tailored classical and nonclassical states of light using nanostructured and integrated optical systems as well as the use of nonclassical light for imaging and sensing. This includes the following research fields: • Integrated quantum optics • Nonlinear optics in waveguide and nanostructures • Photon-pair generation • Quantum imaging and sensing TEACHING FIELDS Dr. Setzpfandt currently teaches master-level courses on: • Quantum Optics • Quantum Imaging and Sensing • Integrated Optics • Experimental Quantum Technologies RESEARCH METHODS Dr. Setzpfandt uses a number of state-of-the-art characterization techniques, e.g.: • Nonlinear frequency conversion and nonlinear spectroscopy • Photon-pair correlation measurements • Quantum ghost imaging • Integrated optical circuit characterization RECENT RESEARCH RESULTS Photon pairs, quantum states of light containing exactly two photons, are the basis for many quantum phenomena and quantum applications in computing, communication, and sensing. They are often generated using spontaneous down-conversion (SPDC), a second-order nonlinear conversion process where a shortwavelength pump photon decays into a pair of signal and idler photons. The properties of these photon pairs can be controlled to a large extent by the properties of the nonlinear optical material they are generated in. One focus of our research is to use structured nonlinear materials in the form of waveguides or nanophotonic resonators to generate tailored photon pairs, where we could show the generation of spatially entangled pairs in nanostructured waveguides [1] and develop a complete understanding of the states that can be generated in coupled waveguide systems [2]. Furthermore, we could show that waveguide sources of photon pairs can be directly used as a spectroscopic sensor, where, using quantum correlations, spectroscopy in the mid-IR can be performed by measuring only photons in the visible [3, 4]. We also investigate the applications of photon pairs for quantum imaging, where we recently found a lensless quantum imaging method reminiscent of a pinhole camera [5]. Whereas nonlinear waveguides are an established platform for generating photon pairs, nanostructured nonlinear surfaces are currently emerging and enable precise control of the emission direction of photon pairs by lateral structuring. The potential of this approach was demonstrated for a surface of monomolecular thickness using classical frequency conversion, which follows the same rules as SPDC [6]. WAVEGUIDES FOR QUANTUM SPECTROSCOPY Nonlinear waveguides enable the generation of photon pairs with largely different wavelengths, e.g. with one wavelength in the mid-IR and the other in the visible. This renders them promising devices for quantum spectroscopy, where the mid-IR photon can interact with substances in the waveguide surrounding and its absorption can be sensed by measuring only the visible partner photon. This enables IR spectroscopy using cheaper and more sensitive detectors for visible light. We recently could experimentally demonstrate the feasibility of this concept be generating photon pairs with one photon in the mid-IR in a waveguide and inferring waveguide properties in this spectral range from measurements of the short-wavelength partner photon only. [1] Saravi et al., Opt. Lett. 44, 69 (2019). [2] Belsley et al., Opt. Express 28, 28792 (2020). [3] Kumar et al., Phys. Rev. A 101, 053860 (2020). [4] Solntsev et al., APL Photonics 3, 021301 (2018). [5] Vega et al., Appl. Phys. Lett. 117, 094003 (2020). [6] Löchner et al., Opt. Express 27, 35475 (2019). Contact: Phone: +49 3641 947569 Email: f.setzpfandt@uni-jena.de
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