Growth, thermal, and spectroscopic properties of a Cr,Yb,Ho,Eu:YAP laser crystal

• A new Cr,Yb,Ho,Eu:YAP laser crystal was grown by the CZ method for the first time.
• Thermal properties indicate the suitable crystal growth direction is the b axis.
• Spectroscopic measurements show Cr3+ and Yb3+ can act as sensitizers of Ho3+ ions.
• Eu3+ ions can act as deactivator in decreasing threshold and increasing efficiency.

A new Cr,Yb,Ho,Eu:YAlO3(YAP) laser crystal was successfully grown by the Czochralski method. Thermal properties were investigated along the a, b, and c crystalline axes. Results indicate that the Cr,Yb,Ho,Eu:YAP crystal has large anisotropic thermal expansion and that the suitable crystal growth direction is the b axis. The Debye temperatures were fitted, and the lattice vibration frequencies were calculated. Spectroscopic measurements show that Cr3+ and Yb3+ can be used as sensitizers of Ho3+ ions, and Eu3+ ions can play a role of the deactivator in decreasing the lifetime of laser lower level 5I7 from 8.69 ms to 1.89 ms, which is beneficial in decreasing laser threshold and increasing laser conversion efficiency. All these findings suggest that the Cr,Yb,Ho,Eu:YAP crystal is a new potential candidate for realizing 2.8–3 μm laser output pumped by a 970 nm laser diode or pulsed flash lamp.