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Department of Physics

Extreme nonlinearities within a quantum cascade laser

Quantumcascadelaser © Christoph Lange​/​TU Dortmund

Teaming up with partners from Germany, France, UK and Sweden, we observed high-order terahertz nonlinearities in a free-running quantum cascade laser. Nonlinearities up to eight-wave-mixing as well as the subcycle gain dynamics were revealed by two-dimensional terahertz spectroscopy in a regime of negative absorption. Potential future applications include efficient intracavity frequency conversion under optical gain and mode proliferation to passive mode locking.

The results have been published in Light: Science & Applications.