A.A. Demidovich

All solid-state diode-pumped Raman laser with self-frequency conversion

Operation of an all solid-state compact pulsed Raman laser pumped by a continuous-wave laser diode is demonstrated. The Stokes and anti-Stokes radiations of stimulated Raman scattering at the 1.181 and 0.973 μm wavelengths, respectively, are generated as a result of self-frequency conversion of the 1.067 μm laser radiation in a Nd3+:KGd(WO4)2 crystal. With Q-switched operation, the Raman laser threshold corresponds to 230 mW of a laser diode light power. The output power of 4.8 mW is achieved at the Stokes wavelength with a kilohertz repetition rate.

Continuous-wave Raman generation in a diode-pumped Nd 3+ :KGd(WO 4 ) 2 laser

Continuous-wave Raman generation in a compact solid-state laser system pumped by a multimode diode laser is demonstrated. The Stokes radiation of stimulated Raman scattering at 1.181 microm is generated as a result of self-frequency conversion of the 1.067 microm laser radiation in Nd3+:KGd(WO4)2 crystal placed in the cavity. The Raman threshold was measured at 1.15 W of laser diode power. The highest output power obtained at the Stokes wavelength was 54 mW. The anomalous delay of Raman generation relative to the start of laser generation (the oscillation buildup) due to slow accumulation of Stokes photons in the cavity at low Raman gain and Raman threshold dependence not only on the laser intensity but also on the time of laser action are observed.

Efficient diode-pumped passively Q-switched laser operation around 1.9 μm and self-frequency Raman conversion of Tm-doped KY(WO4)2

Passively Q-switched operation of Yb,Tm:KY(WO4)2 and Tm:KY(WO4)2 lasers diode pumped at 805 nm has been investigated. A thin plate of Cr:ZnS was used as a saturable absorber for passive Q switching. A maximum average output power of 116 mW emitted at 1.9 μm in comparison to 160 mW for the free-running regime at the same pumping level has been obtained with a slope efficiency of 26% with respect to the incident pump power. Using a Tm:KYW sample with broadband antireflection coatings and dichroic laser resonator mirror, the first Stokes component of Raman self-frequency conversion was observed at 2365 nm.

Influence of Yb concentration on Yb:KYW laser properties

CW and Q-switched KY(WO 4 ) 2 :Yb 3+ with ytterbium concentration of 5%, 10%, and 20% laser operation under LD pumped have been investigated and the main characteristics of the KY(WO 4 ) 2 :Yb 3+ laser are presented here. A maximum slope efficiency of 66% was achieved for this active medium.

Stimulated Raman scattering in Nd:KGW laser with diode pumping

Operation of an all solid-state compact pulsed Nd:KGW Raman laser pumped by a cw laser diode is demonstrated. The Stokes and anti-Stokes radiations of stimulated Raman scattering at the 1.181 μm and 0.973 μm wavelengths, respectively, are generated as a result of self-frequency conversion of the 1.067 μm laser radiation in a Nd:KGW crystal. With Q-switched operation the Raman laser threshold corresponds to 230 mW of a laser diode light power. The output power of 8.9 mW is achieved at the Stokes wavelength with a kilohertz repetition rate. Blue luminescence trace in Nd:KGW crystal under simultaneous 1.067 μm laser action and Raman generation is observed. A possible mechanism of this up-conversion process is proposed.

Optical characterization of Yb,Tm:KYW crystal concerning laser application

Abstract Absorption and emission spectra as well as 2F5/2(Yb3+) and 3H4,3F4(Tm3+) excited state relaxation of Yb:Tm-doped potassium yttrium tungstate (KY(WO4)2) crystal were measured. The intensities of the electronic transitions were analyzed from the point of view of further application of this crystal for diode pumped solid-state lasers. The processes of energy transfer between Yb and Tm ions under 980-nm excitation in this medium are discussed.

Blue up-conversion emission in Yb- and Tm-codoped potassium yttrium tungstate

The spectroscopic characteristics of potassium yttrium tungstate crystal (KYW), codoped with ytterbium and thulium ions, have been investigated from the point of view of up-conversion blue lasing from 1G4 multiplet. An overall 3H6 multiplet splitting of ∼530 cm−1 for the trivalent thulium ion in the KYW host was obtained. A decay time of ∼112 μs for the 1G4→3H6 blue luminescence in the material doped by 1 at.u200a% of thulium was measured. The value of peak emission cross section for this transition is estimated to be (1.8±0.3)×10−20u200acm2. Strong cross-relaxation quenching was found to be one of the main channels of nonradiative losses from the 1G4 and 3H4 multiplets. The cross-relaxation rate was significantly higher at higher concentration of thulium.

A 1.35 μm laser diode pumped continuous wave KGW:Nd laser

Abstract A 1.35 μm continuous-wave laser operation in potassium gadolinium tungstate (KGd(WO 4 ) 2 :Nd 3+ or KGW:Nd) under laser diode end-pumping have been achieved. The effects of wavelength variations of the pump source on the stability of the solid-state laser output power and efficiency have been investigated. Second harmonic generation has been obtained for an intracavity configuration.

Passive Q-switching of laser diode pumped LBGM:Nd laser

Abstract A new efficient laser solid state medium Nd:LBGM (Li3Ba2Gd3(MoO4)8:Nd3+) was used as a diode pumped laser with passive Q-switching. The performances of continuous wave (CW) and passive Q-switched Nd:LBGM lasers under a CW laser diode (LD) with low pump power have been investigated.