“…The availability of light sources with specific and tunable spectral properties is of interest in many fields of physics, from spectroscopy [1,2,3] to spectral imaging [4], from optical sensing to material processing [5,6]. Solid state lasers [7,8,9] may offer the chance for tuning the laser wavelength in a limited range. Other more complex lasers, such as dye lasers, can also provide wider wavelength tuning ranges.…”