Solid-state lasers are characterised mainly by their high efficiency and compactness. Since the emission wavelengths of these lasers are determined by the spectral and crystallographic properties of the solid-state medium, not all wavelength ranges are directly accessible.
For the detection of pollutants and hazardous substances or atmospheric trace gases, for example, laser sources with emissions in the ultraviolet are needed for laser-induced fluorescence (LIF) measurements or mid-infrared lasers are required for measuring molecular rotational and vibrational spectra. By employing nonlinear frequency conversion, frequency multiplication and by using optical parametric oscillators and amplifiers, the required emission wavelengths can be specifically generated for the respective application.