| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 734439 | Optics & Laser Technology | 2013 | 8 Pages |
An innovative architecture for edge-pumped high power microchip laser is introduced. This geometry consists of a Yb:YAG thin disk gain media surrounded by an irregular octagonal undoped YAG cap as pumping light waveguide. The main advantages of the new geometry are high uniform absorption distribution, high absorption efficiency and simple construction to fabricate. Using the Monte Carlo ray tracing method, the pumping process and absorption profile in active medium are simulated. In addition, considering the impact of Yb+3 doping concentration and temperature on thermal conductivity, and based on the finite-difference method the conduction equation was solved and the temperature distribution in the gain media calculated. Based on these simulations, influence of active medium parameters such as core diameter, doping concentration and octagon side sizes ratio on absorption profile and efficiency as well as maximum temperature in gain medium is investigated. High absorption efficiency (over 94%) with perfect top-hat absorption profile has been predicted to be obtained from the designed microchip with optimized parameters. This microchip has a core diameter of 4 or 5 mm, 9 at% Yb3+ doping concentration and 300 μm thickness. An estimation based on laser rate equations shows that with 960 W pumping power, more than 600 W output power (optical efficiency of 66%) can be extracted from the designed system.
► We proposed a new geometry for Yb:YAG microchip that improves the laser absorption. ► This geometry is an octagonal YAG waveguide surrounding a thin disk Yb:YAG core. ► The optimum values of the new microchip specifications are determined. ► Temperature analysis of the microchip is performed based on the conduction equations. ► 600 W output power with 60% optical efficiency is extractable from this microchip laser.
