Group Nonlinear Optics and Quantum Sensing

Innovative new measurement technologies are at the core of the group’s research: What types of sensors will we use tomorrow? And what sorts of opportunities will this open up?

In close cooperation with partners in basic research, the group is working on innovative laser-based measurement principles and methods for spectroscopy and magnetometry. This includes the development of tools such as light sources and wavelength converters based on nonlinear frequency conversion and also the components needed such as periodically-poled crystals or functionalized waveguides.

The group is also conducting research in the field of quantum sensor technology, where nonlinear frequency conversion enables creating pairs of photons with different wavelengths, which are “entangled” in terms of their properties. They form the basis of a Quantum Fourier Transform Infrared Spectrometer, which is designed to enable measurements with very low optical power.

We use alkali atoms for magnetic field sensing by preparing the atoms in defined spin quantum states. This turns them into highly sensitive magnetic field sensors for which the team is identifying new fields of application in industrial process measuring technology.

Nonlinear optics

• Optical parametric oscillators: continuous-wave, wavelength tunable from 450 nm to 5 μm, power outputs from 10 mW up to many watts (wavelength-dependent), linewidth of less than 1 MHz
• Frequency doubling: conversion efficiency of over 50 percent
• MIR-NIR conversion for rapid and efficient measuring technology: MIR process data recorded at more than 5000 spectra per second, highly precise wavelength measurement
• Lightsources based on spontaneous parametric down conversion for quantum sensing

Components

• Maskless poling of materials designed for frequency conversion
  
• Lithium niobate-on insulator as starting material for integrated-optical components
• Waveguides, resonators and frequency converters

Quantum sensor technology

• Spectroscopy: Quantum Fourier Transform Infrared Spectrometer based on entangled photon pairs
  
• Magnetic field sensors: NMR at ultra-low magnetic fields thanks to optically pumped magnetometers