US Patent 7443900 Laser gain medium for solid state dye lasers

The present invention relates to a laser gain medium comprising at least one active species adapted to be stimulated to emit laser light within a predetermined wavelength range and optical feedback means defining a resonator for said laser light. The feedback means comprise at least one substantially solid cholesteric layer having a substantially planar texture exhibiting selective reflection of light defined by a reflection band tuned to said predetermined wavelength range.