Comprehensive Thermal Analysis of Diamond in a High-Power Raman Cavity Based on FVM-FEM Coupled Method

Abstract

Despite their extremely high thermal conductivity and low thermal expansion coefficients, thermal effects in diamond are still observed in high-power diamond Raman lasers, which proposes a challenge to their power scaling. Here, the dynamics of temperature gradient and stress distribution in the diamond are numerically simulated under different pump conditions. With a pump radius of 100 μm and an absorption power of up to 200 W (corresponding to the output power in kilowatt level), the establishment period of thermal steady-state in a millimeter diamond is only 50 μs, with the overall thermal-induced deformation of the diamond being less than 2.5 μm. The relationship between the deformation of diamond and the stability of the Raman cavity is also studied. These results provide a method to better optimize the diamond Raman laser performance at output powers up to kilowatt-level.

Numerical Simulation of Long-Wave Infrared Generation Using an External Cavity Diamond Raman Laser

“…The simulation results in this study provide important theoretical guidance and prediction for the subsequent development of LWIR lasers based on the DRL. In addition, due to the excellent thermophysical properties of diamond, stable LWIR Raman operation without heat accumulation can be realized when the pump pulse width is in the order of 100 microseconds, meanwhile, the repetition rate can be up to kHz-level [10,25], even if its quantum defect is significantly higher than that of the short wave. As there is no spatial hole burning effect in the process of Raman conversion [26][27][28][29], the theoretical study also provides a preliminary reference for realizing the operation of narrow linewidth LWIR lasing.…”

Femtosecond Laser Processing Technology for Anti-Reflection Surfaces of Hard Materials

“…Diamond is transparent in the visible, ultraviolet, and infrared regions, and possess a thermal conductivity for more than 20 W cm −1 K −1 at room temperature. In addition, it features chemical inertness, radiation stability, and biocompatibility [ 114 ], enabling its applications in ultra-high precision machining tools [ 115 ], microelectromechanical systems (MEMS) [ 116 ], sturdy optical gratings [ 117 ], high power lasers [ 118 , 119 , 120 ], and electronic devices suitable for harsh environments [ 121 ].…”

Developments of Picosecond Lasers Based on Stimulated Brillouin Scattering Pulse Compression

“…Among them, the solid media has good thermal conductivity and no thermal convection effect, but its damage threshold is relatively low. As a new solid gain medium discovered in recent years, diamond crystal has attracted extensive attention because of its high Brillouin gain coefficient, high thermal conductivity, and wide spectral transmission range [117][118][119][120]. Once it breaks through the size limit, its application prospect in SBS pulse compression will be very promising.…”