Nonlinear frequency conversion

When nonlinear optical materials are exposed to intense laser radiation, processes are triggered that can generate light with different wavelengths. These processes include frequency doubling, sum-frequency generation, and optical-parametric generation.

The most well-known one is frequency doubling, used in green laser pointers, for example. Optical-parametric generation converts a fixed pump frequency into tunable laser light by using quasi-phase-matched materials. Optical parametric oscillators based on periodically-poled lithium niobate or lithium tantalate emit light from the visible to the terahertz frequency range. Among other things, sum-frequency generation is employed to transfer light with wavelengths from the mid-infrared range into the wavelength range below 1 µm in order to detect it by using standard silicon detectors and pixel sensors.

The main research focus at Fraunhofer IPM lies on frequency converters such as optical parametric oscillators (OPO), SHG modules and frequency mixers based on continuous wave lasers for industrial partners and end customers. They allow for generation of single-frequency radiation in the UV, VIS, NIR and MIR up to several watts of power - for example for spectroscopic and holographic applications.

Fraunhofer IPM has many years of experience with nonlinear optical materials such as lithium niobate and lithium tantalate. In addition, fundamental research carried out at the associated Laboratory for Optical Systems at the University of Freiburg gives us access to the latest research findings in this field.