Spectroscopy registers the interaction between matter and electromagnetic radiation. Spectroscopic data is mostly represented in a spectrum, where the intensity of the interaction is plotted versus the wavelength. It can also be represented in a data output or in an image if correct signal analysis is performed. At our department, we are working with development and applications of several optical spectroscopy techniques. For instance, we use visible and infrared spectroscopy to characterize snow and different surfaces at cold temperatures. We also perform Raman spectroscopy and develop holographic stimulated Raman spectroscopy to study gases, tissue and single cells.