Highly Efficient, Compact Tm3+:RE2O3 (RE = Y, Lu, Sc) Sesquioxide Lasers Based on Thermal Guiding

Identifier:  imarina:3823821

Handle: https://hdl.handle.net/20.500.11797/imarina3823821

Authors:  Loiko, P; Koopmann, P; Mateos, X; Serres, JM; Jambunathan, V; Lucianetti, A; Mocek, T; Aguiló, M; Díaz, F; Griebner, U; Petrov, V; Kränkel, C

Abstract:
© 1995-2012 IEEE. Cubic sesquioxides, RE 2 O 3 , where RE = Y, Lu or Sc, are attractive host crystals for thulium (Tm 3+ ) doping. A comparison of the spectroscopic properties of Tm 3+ :RE 2 O 3 crystals in terms of transition cross sections and cross-relaxation (CR) efficiency required for efficient upconversion pumping is presented. Thermo-optic properties of Tm 3+ :RE 2 O 3 crystals (thermal lensing, fractional heat loading, and thermo-optic coefficients) are described. The positive thermal lens, broadband emission, and efficient CR of the Tm:RE 2 O 3 crystals enable the development of compact, highly efficient and power-scalable lasers operating above 2 ?m, based on thermal guiding. Nowadays, Tm:Lu 2 O 3 microchip lasers are capable of generating nearly 5 W of output power at ?2.06 ?m with a slope efficiency ? of 67% and in a rod geometry-up to 47.5 W with ? of 59%. For multiwatt output at even longer wavelengths around 2.15 ?m, Tm:Sc 2 O 3 is an interesting candidate.