β-Ga2O3 Used as a Saturable Sbsorber to Realize Passively Q-Switched Laser Output

Baizhong Li,Hongji Qi,Qinglin Sai,Peixiong Zhang,Ruifeng Tian,Changtai Xia,Mingyan Pan,Bin Wang,Zhenqiang Chen,Lu Zhang,Qiudi Chen,Youchen Liu

doi:10.3390/cryst11121501

Abstract

β-Ga2O3 crystals have attracted great attention in the fields of photonics and photoelectronics because of their ultrawide band gap and high thermal conductivity. Here, a pure β-Ga2O3 crystal was successfully grown by the optical floating zone (OFZ) method, and was used as a saturable absorber to realize a passively Q-switched all-solid-state 1 μm laser for the first time. By placing the as-grown β-Ga2O3 crystal into the resonator of the Nd:GYAP solid-state laser, Q-switched pulses at the center wavelength of 1080.4 nm are generated under a output coupling of 10%. The maximum output power is 191.5 mW, while the shortest pulse width is 606.54 ns, and the maximum repetition frequency is 344.06 kHz. The maximum pulse energy and peak power are 0.567 μJ and 0.93 W, respectively. Our experimental results show that the β-Ga2O3 crystal has great potential in the development of an all-solid-state 1 μm pulsed laser.

Highlights

It is well known that saturable absorbers play an important role in Q-switching and mode locking operation [1,2,3,4]
~1 μm near-infrared lasers, which have the advantages of high pulse energy and high peak power, can be widely used in space communication, nonlinear spectroscopy, biomedicine, military, and many other fields [13,14,15]
The sintered rod and seed were rotated at 10 rpm in opposite directions, and the crystal was grown in flowing air at a speed of 6 mm/h

Summary

Introduction

It is well known that saturable absorbers play an important role in Q-switching and mode locking operation [1,2,3,4]. We have successfully grown high-quality β-Ga2 O3 using the optical floating zone (OFZ) method, which is a method of growing crystals without a crucible, and is usually used to study and explore the properties of materials This method has the advantages of simple operation, few equipment requirements, and the ability to even grow crystals in the air environment. V3+ :YAG, the thermal conductivity of the β-Ga2 O3 crystal is about 27 W·m−1 ·K−1 , which is much larger than that of ZnS(0.561 W·m−1 ·K−1 ), LaMgAl11 O19 (2.55 W·m−1 ·K−1 ), and YAG(12.9 W·m−1 ·K−1 ) [34,35,36,37,38,39,40] This indicates that the β-Ga2 O3 crystal is favorable for the output of laser pulses with a high peak power and high repetition rate. We believe that our work will provide an important reference for the potential applications of nonlinear optical devices related to crystal growth and optical modulation

The Preparation and Characterization of β-Ga2 O3

Results and Discussion

SA is inserted between

Conclusions