Sub-100 fs mode-locked Tm:CLTGG laser.

Li Wang,Zhongben Pan,Uwe Griebner,Valentin Petrov,Weidong Chen,Ji Eun Bae,Fabian Rotermund,Xavier Mateos,Pavel Loiko

doi:10.1364/oe.435947

Abstract

We report on the first sub-100 fs mode-locked laser operation of a Tm3+-doped disordered calcium lithium tantalum gallium garnet (Tm:CLTGG) crystal. Soliton mode-locking was initiated and stabilized by a transmission-type single-walled carbon nanotube saturable absorber. Pulses as short as 69 fs were achieved at a central wavelength of 2010.4 nm with an average power of 28 mW at a pulse repetition rate of ∼87.7 MHz. In the sub-100 fs regime, the maximum average output power amounted to 103 mW.

Highlights

Calcium niobium gallium disordered cubic garnets of the Ca3(Nb,Ga)5O12 type or shortly CNGG, including those co-doped with univalent alkali metal cations such as Na+(CNNGG) or Li+ (CLNGG), when doped with trivalent rare earth ions (RE3+ = Nd3+ or Yb3+), feature significant inhomogeneous spectral broadening induced by their intrinsic structure disorder while preserving moderate thermal conductivity [1]
The performance of the CW tantalum gallium garnet (Tm):CLTGG laser was evaluated with a four-mirror cavity including a flat rear mirror M3 and a plane-wedged output coupler (OC) without saturable absorber (SA), see Fig. 2
The round-trip cavity loss δ and the intrinsic slope efficiency η0 which is related to the mode matching efficiency as well as the pump quantum efficiency were estimated with the Caird analysis by fitting the measured slope efficiency as a function of the OC

Summary

Introduction

Calcium niobium gallium disordered cubic garnets of the Ca3(Nb,Ga)5O12 type or shortly CNGG, including those co-doped with univalent alkali metal cations such as Na+(CNNGG) or Li+ (CLNGG), when doped with trivalent rare earth ions (RE3+ = Nd3+ or Yb3+), feature significant inhomogeneous spectral broadening induced by their intrinsic structure disorder while preserving moderate thermal conductivity [1]. They have been proven to be excellent gain media for generation of femtosecond pulses at ∼1 μm [2,3,4,5,6,7]. We present the first soliton ML operation of a Tm:CLTGG laser delivering pulses as short as 69 fs at 2010.4 nm

Experimental configuration

Continuous-wave laser operation

Soliton mode-locked operation

Conclusion