# The Laser Physics Group

Our group works with development and applications of various types of laser-based measurement techniques. Spectroscopic techniques are developed for Analytical Laser Spectroscopy, in particular for ultra-sensitive trace gas detection, and Refractometry techniques for assessment of gas refractivity, number density, and pressure, all by optical means.

Due to the unique properties of laser light, laser-based techniques have the potential to be used for a variety of applications.

Free atoms and molecules can interact with light only at very specific wavelengths, corresponding to transitions between discrete energy levels. Since laser light often consists of very narrow linewidth (or monochromatic) light, it can very efficiently be used to probe the structure of such species. However, it can also be used to detect and quantitatively assess their presence. Properly developed, such techniques can acquire extraordinary high sensitivity and selectivity, allowing for detection of minute concentrations of a variety of species under various types of conditions. The techniques can, for example, often outperform conventional techniques for trace element and trace gas analysis and be used for environmental monitoring. When used for the former types of applications, the field is often called Analytical Laser Spectroscopy.

Another type of application of laser light is to assess the refractivity (i.e. the index of refraction) of gases by the use of interferometric techniques. Since refractivity can be connected to gas density and pressure, Refractometry techniques are developed for assessment, by purely optical means, of the refractivity, the (number) density, and the pressure of gases. If developed properly, they have the potential to replace current density and pressure standards.