We synthesized a series of sol-gel silica matrices doped with laser dyes DCM, LK678, LD1, and LD2 which alcohol solutions have efficient lasing in the red spectral region and Rh800-in the near infrared (NIR) one. Absorption, fluorescence, and laser properties of the dyes in silica samples prepared by sol-gel process were investigated. It has found some peculiarities in preparation process of the laser matrices and in spectral characteristics of the dyes in these matrices.
IntroductionThe lasers tuned in the red and the near infrared (NIR) regions of the spectrum and dyes-sensitizers for this spectral range are widely applied for diagnostics of different biological and medical objects. For instance, an oxazine dye [1] is used for early diagnostics of Alzheimer's disease. The urgency of laser sources for this region is due to the fact that the penetration depth of the radiation into living tissue for them is about a centimeter. Furthermore study of new photosensitizers with the silica coating for photodynamic therapy at infrared excitation [2] necessitates quest of new radiation sources.Dye lasers developed specially may be used for this purpose. However, for many practical applications solid-state dye lasers are the most challenging because of they are not required bulky dye-flow systems, and no toxic and inflammable solvents [3]. Matrices prepared by the sol-gel process, polymeric ones or porous glasses are used in these lasers.