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| The present study addresses a novel cooling scheme for the high-power solid-state laser slab. The scheme cools the laser slab by forced convection in a narrow channel through a heat sink. Numerical simulations were conducted to investigate the thermal effects of a Nd:YAG laser slab for heat sinks of different materials including the undoped YAG, sapphire and diamond. The results show that the convective heat transfer coefficient is non-uniform along the fluid flow direction due to the thermal entrance effect, causing a non-uniform temperature distribution in the slab. The heat sink lying between the coolant fluid and the pumped surface of the slab works to alleviate this non-uniformity and consequently improves the thermal stress distribution and reduces the maximum thermal stress of the slab. It is found that the diamond heat sink is effective in reducing both the highest temperature and the maximum thermal stress, the sapphire heat sink is able to reduce the maximum thermal stress but is not so effective in reducing the highest temperature, the undoped YAG heat sink reduces the maximum thermal stress but tends to increase the highest temperature. Therefore, cooling with the diamond heat sink is most effective, that with the sapphire heat sink follows, whereas that with the undoped YAG heat sink may not apply if the highest temperature is a concern. |
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| Keywords: Laser cooling; forced convection; heat sink; thermal effect. |
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