Technology Overview

High power solid-state lasers have many applications in industry, medicine, and scientific research. Currently, the mainstream solid-state laser gain media used are the rare-earth doped YAG (Yttrium Aluminium Garnet) single crystals. For high power laser operation, the thermal-optical properties of the laser gain medium such as the thermal conductivity and photon energy plays an essential role.

As yttria has larger thermal conductivity and lower phonon energy than YAG, yttria-based laser gain media could potentially have better high-power laser performance. However, due to the high melting point of yttria, it is very challenging to grow yttria crystals. The research team has developed a unique low temperature vacuum sintering plus hot isostatic pressing method for fabricating high lasing efficiency, yttria-based laser ceramics that can be used to replace the YAG-based laser gain media for better laser operation but with lower cost.

Technology Features, Specifications and Advantages

Yttria ceramics with the following properties can be fabricated:

• Large size (up to 50 mm × 10 mm in diameter)
• Transparent with sub-micro grain sizes
• Doped with different rare-earth ions, such as Nd3+, Yb3+, Er3+, Tm3+, Ho3+, Dy3+, at different doping concentrations

Potential Applications

The doped ceramics can be used as high efficiency laser gain media for high power 1 µm, 2 µm and 3 µm lasers.

Example 1: Using a 3 at.% Yb3+:Y2O3 ceramic, 33 W continuous wave (CW) laser emission at 1.07 µm with an optical-to-optical efficiency of >60% was demonstrated under diode end-pumping.

Example 2: Using a 0.5 at.% Ho3+:Y2O3 ceramic, 210 W CW laser emission at 2.1 µm was obtained under in-band pumping.

Example 3: Using a 7 at.% Er3+:Y2O3 ceramic, 11 W CW laser emission at 2.7 µm was achieved under laser diode end-pumping.

The technical know-how can also be used to fabricate other transparent ceramics used for windows, lenses, transparent armors, phosphors, and scintillators.

Customer Benefit

• Large size
• High efficiency
• High optical quality
• Different rare-earth doping concentrations