1_2W中红外ZnGeP_2光参量振荡器_英文_

　第17卷　增　刊强激光与粒子束Vol.17,No.S0 2005年4月H IGH POWER L ASER AND PAR TICL E B EAMS Apr.,2005　

Article ID:　100124322(2005)S020163204

1.2W Z n G eP2optical parametric oscillator3

WAN G Yue2zhu,　YAO Bao2quan,　J U You2lun,　H E Wan2jun

(N ational Key L aboratory of T unable L aser Technology,Harbin I nstit ute of Technolog y Harbin,150001,China) Abstract:　A doubly resonant Zn G eP2(ZGP)optical parametric oscillator pumped by a Tm,Ho:GdVO4la2

ser is investigated.High pulse repetition f requency of10k Hz cryogenic Tm(5%),Ho(0.5%):GdVO4laser at

2.05μm was utilized as pumping source for Zn G eP2OPO.The stable pulse train with duration of23ns was a2

chieved f rom Tm,Ho:GdVO4laser pumped by a continuous wave fiber2coupled laser diode at801nm.The Gd2

VO4host exhibited good thermo2optical property,experiencing greater than12kW/cm2pump density.The

ZGP OPO generated a total combined output of1.2W at3.75μm and4.52μm under pumping power of5.3

W,corresponding conversion efficiency of23%f rom incident2μm laser power to mid2IR output.

K ey w ords:　Optical parametric oscillator;　Zn G eP2;　Tm,Ho:GdVO4laser

C LC number:　TN248 Document code:　A

High power,high PRF(>10k Hz)t unable solid2state Mid2IR lasers are usef ul in many application areas such as laser radar,chemical detection and countermeasure.Zinc germanium p hosp hide(ZGP)has out stand2 ing f undamental p roperties as a Mid2IR nonlinear crystal.The very high nonlinear2optical coefficient of Zn GeP2(d eff=75p m/V),combined wit h good optical,mechanical,and t hermal p roperties(t hermal conduc2 tivity18W・m-1・K-1),favors efficient high2average2power Mid2IR O PO[1].Recent significant material growt h imp rovement of Zn GeP2makes it possible to produce a crystal wit h low absorption at t he2.05μm p ump wavelengt h(less t han or equal0.1cm-1)or wit h an absorption below0.03cm-1f rom2.6μm to8.4μm.Holmium solid state lasers can be used to p ump ZGP OPO to achieve continuous t unability in t he3～5μm spectral range.In t he most powerf ul mid2IR OPO,reported by Cheung et al,a10W ZGP OPO was p umped at2.05μm using a cryogenic Tm,Ho:Y L F laser[2],and P. A.Budni of Sanders reported a4.2W one p umped by a room temperat ure Ho:YA G laser[3].

The absorption cro ss section of t hulium in GdVO4is considerably st ronger and broader(770～820nm) t han in YA G and YL F,and t he spectrum shift s closer to t he emission wavelengt h of commercially available Al GaAs laser diodes[4].In t his experiment,we used an801nm laser diode as p umping source.Previous re2 sult s wit h Y L F crystals have shown f ract ure when subjected to p ump densities greater t han5kW/cm2.Gd2 VO4ho st and can experience>12kW/cm2p ump density,confirmed by our experiment,allowing to scale up holmium laser average power by end2p umping fabrication wit hout t he requirement of diff usion bonded com2 posite rod[5].The Boltzmann coupling lifetime of t hulium3F4and holmium5I7in GdVO4host is3ms t hat is shorter t han9ms for Tm,Ho:YA G and15ms for Tm,Ho:Y L F[6].The short lifetime,large emission cross section are very favorable for t he Q2switched short p ulse generation operated at repetition rate up to10k Hz. High peak power p ulse wit h short p ulse widt h and stable p ulse t rain was obtained f rom Tm,Ho:GdVO4la2 ser in our experiment.To our knowledge,t he high PRF q2switched Tm,Ho:GdVO4laser is t he first repor2 ted experimental result s.The ZGP O PO p umped by Tm,Ho:GdVO4laser was reported for t he first time.

The gain medium is a codoped5%Tm and0.5%Ho:GdVO4crystal in dimensions4mm(widt h)×4mm (height)×7mm(lengt h).The end faces are antireflection coated for t he laser wavelengt h(R<0.3%)and t he p umping light at801nm(R<1%).This crystal is wrapped wit h indium foil and held in a copper heat2 sink connected wit h a small dewar filled wit h liquid2N2.

3R eceived d ate:2004211222; R evised d ate:2005203230

Found ation item:Supported by t he Scientific Research Foundation of Harbin Institute of Technology(HIT200214)

Biography:Wang Yuezhu(1942—),female,professor,engaged in t he study of solid nonlinear optical application;E2mail:juyl@。