Sergei Sverchkov

Diode-pumped Er–Yb:glass laser passively Q switched by use of Co 2+ :MgAl 2 O 4 as a saturable absorber

We report on passively Q-switched operation of a diode-pumped Er-Yb:glass laser with a Co(2+):MgAl(2)O(4) plate as a saturable absorber. Optical pulses with peak power exceeding 2 kW and a pulse length of 2.3 ns have been generated. Single-longitudinal-mode Q-switched operation at 1.53 mum has been obtained by use of the Co(2+):MgAl(2)O(4) plate as an intracavity etalon. A discussion of the optimal Er(3+) concentration as well as optimization of the cavity design is included.

50 mJ/30 ns FTIR Q-switched diode-pumped Er:Yb:glass 1.54 μm laser

Abstract 50 mJ Q-switched output at 30 ns pulse duration was demonstrated with a transversely diode-pumped bulk Er 3+ :Yb 3+ :glass 1.54 μm laser system of uncomplicated and compact design, using a piezoelectrically driven FTIR shutter. In long-pulse operation, 360 mJ output was obtained for 2.65 J incident optical pump energy. Maximum optical slope efficiencies of 20.5% and 5.4% were measured in long-pulse and Q-switched operation, respectively. Optimum Q-switch timing was studied taking into account the Yb 3+ →Er 3+ energy transfer process and was correlated with free-running delay parameters.

New crystalline material for 1.5 micrometer lasers: Yb,Er-activated GdCa4O(BO3)3

A new crystalline medium for 1.5 micron Yb-Er lasers is proposed: GdCa4O(BO3)3 (GdCOB). Its melting point allows crystal growth using Pt instead of Ir crucibles. Spectroscopic and laser tests of the new material are described.

Co 2+ :MgAl 2 O 4 crystal passive Q-switch performance at 1.34,1.44 and 1.54 micron

Cobalt doped materials, such as Co2+:ZnSe[1,2], Co2+:YSGG, and Co2+:MgAl2O4[3,4], have shown promise for use as high performance saturable absorber Q-switches for near infrared lasers.

Method For Compensation Of Thermal Lensing In Slab Lasers

The very efficient phosphate glasses of high Nd3+ concentration have relatively (compared to YAG) low thermooptical parameters. In the athermal glasses the thermomechanical stress leads to fraction at moderate average pumping already. Slab geometry with higher than 2.1 width to thickness ratio ensures higher fraction threshold than that of a cylindrical rod of the same cross section, but the thermal lensing causes high-pumping rate dependent-divergence. To compensate the lensing in a relatively wide pumping/repetition rate range a cylindrical resonator was used. With cylindrical mirrors the output beam stability was excellent.