Superior performance of a 2  kHz pulse Nd:YAG laser based on a gradient-doped crystal

Abstract

Herein, we report a homemade new Nd:YAG crystal rod that contains a gradient dopant of 0.39–0.80 at.% Nd 3 + from end to end, achieving superior performance of a 2 kHz Nd:YAG pulse laser at 1064 nm. The optical-to-optical conversion efficiency reached 53.8%, and the maximum output power of the laser was 24.2 W, enhanced by 35.9% compared with a uniform crystal rod with the same total concentration of Nd 3 + . Significantly, our experiments revealed that the gradient concentration crystal produced a relatively even pumping distribution along the rod axis, greatly reducing the temperature gradient as well as having a smaller thermal effect. The pump and thermal distribution smoothing obviously improved the features of laser oscillation and output.

Surface Structure and Electronic Properties of Lu3Al5O12

“…The garnet(A 3 B 5 O 12 ) single crystal is a type of material that has been widely used in photonics for a long time [1][2][3][4] and its scintillation characteristics are currently being investigated because of a demand in the detection system [5,6]. Moszynski first characterized the scintillation performance of Y 3 Al 5 O 12 (YAG) [7].…”

“…Moszynski first characterized the scintillation performance of Y 3 Al 5 O 12 (YAG) [7]. With respect to YAG, LuAG doped with Ce ions has a relatively high density (6.73 g/cm 3 ) and the scintillation efficiency is 7 or 8 times than that of BGO (Bi 4 Ge 3 O 12 ) [8]. However, the light yield and decay time of LuAG is 3 times [9] and one fifth of that of BGO [10,11] respectively, once doped with active ions.…”

Growth of a Gradient-Doped Single-Crystal Rod with Designable Distribution of Doped Ions by a Laser-Heated Pedestal Growth Method

“…When the GDC rod is pumped from the end face of low doping ions, less heat is generated on the pump incident end face, and the temperature distribution along the pump direction is more uniform, which can effectively reduce the thermal lens and improve the oscillation efficiency of the laser. On the contrary, when the UDC rod is end-pumped, the heat is mainly concentrated on the end-pumped surface, and the temperature gradient distribution is large, resulting in a serious thermal lens effect, which leads to the reduction of the fundamental mode volume of the planar parallel resonator and the reduction of the output power …”

“…In this way, the overall temperature difference of the gain medium is reduced to improve the thermal effect in laser generation. − However, this bonding technology requires very strict flatness and cleanliness of the bonding surface, so the preparation process is more cumbersome. At the same time, the doping concentration at the interface of different crystal bonding is almost mutated, which will affect laser oscillation and amplification . Preparing the crystal into a fiber shape, that is, single-crystal fiber, can also effectively increase the heat dissipation during the operation of the DPSSL. − …”

High-efficient diode-end-pumped actively Q-switched Nd:YAG/Nd:YVO4 laser

“…An a-cut Nd:YVO 4 crystal with the dimensions of 3×3×20 mm 3 and the doped concentrations of 0.18-at.% was set behind the Nd:YAG crystal to absorb the residual pump light. This dual-crystal structure can sustain high thermal load and pump power, which is similar to the structure adopted in [17] and [18]. The two crystals provided laser gain together.…”