One Light Source — All Colors

A single source emitting single‐frequency light with tunable color and without the need of changing toxic chemicals, as it is the case for dye lasers, is desired by many scientists. The Department of Microsystems Engineering IMTEK at the University of Freiburg together with the Fraunhofer Institute for Physical Measurement Techniques IPM now extend the tuning range of continuous‐wave optical parametric oscillators into the visible spectrum by integrated, intra‐cavity frequency doubling. Combination of these two nonlinear‐optical effects enables the operator to deliberately choose any wavelength between 430 and 690 nm.