TmYAG

TmYAG refers to thulium-doped yttrium aluminum garnet, a solid-state laser gain medium in which thulium ions (Tm3+) substitute for yttrium sites in Y3Al5O12 (YAG). The YAG host provides a transparent, mechanically robust crystal with favorable thermal properties, making it suitable for stable, high-power operation.

In Tm:YAG, the laser transition occurs primarily from the upper level 3F4 to the ground manifold 3H6, producing emission near 2.0 micrometers. Typical pumping uses near-infrared diode light in the vicinity of 0.8 to 1.0 micrometers. Absorption of the pump promotes ions to higher Stark levels, which rapidly relax nonradiatively to the 3F4 level; radiative decay then yields photons around 2.0 μm. The emission band is relatively broad, supporting simple laser design and potential tuning or short-pulse operation in certain configurations.

Doping levels in YAG crystals are usually on the order of a fraction of a percent to a couple of percent, chosen to balance gain against concentration quenching and thermal effects. Crystals are commonly grown by established methods such as the Czochralski process, producing high-quality single crystals suitable for laser cavities.

Applications of Tm:YAG span medical, sensing, and industrial fields. It is used for compact, infrared lasers in the near- to mid-infrared region, including medical soft-tissue procedures and dental work, as well as lidar and spectroscopy. The 2 μm emission is also exploited as a pump source for optical parametric oscillators to generate longer-wavelength mid-infrared radiation.