A solid state laser in which the active medium is a glass host that supports the active species. The neodymium-doped phosphate glass laser is one example.
Source:
PAC, 1995, 67, 1913. 'Nomenclature, symbols, units, and their usage in spectrochemical analysis-XV. Laser-based molecular spectroscopy for chemical analysis - laser fundamentals (IUPAC Recommendations 1995)' on page 1920 (https://doi.org/10.1351/pac199567111913)