Development of an eye-safe solid-state tunable laser transmitter around 1.45 {_m63m [my-m] based on Cr_1hn4_1hn+:YAG crystal for lidar applications [Elektronische Ressource] / vorgelegt von Anna Petrova-Mayor

Description

Development of an eye-safe solid-statetunable laser transmitter around 1.45μm4+based on Cr :YAG crystal for lidarapplicationsDissertation zur Erlangung des Doktorgradesder Naturwissenschaften (Dr. rer. nat.)Fakult¨at NaturwissenschaftenUniversit¨at HohenheimInstitut fu¨r Physik und Meteorologievorgelegt vonAnna Petrova-Mayoraus Vratsa, Bulgarien2008Thisthesiswasacceptedasadoctoraldissertationinfulfillmentoftherequirementsforthedegree“DoktorderNaturwissenschaften”bytheFacultyofNaturalSciencesat the Universityof Hohenheim, Stuttgart, Germany on 24 October 2007.Date of oral examination: 2 April 2008Examination committee:Supervisor and reviewer: Prof. Dr. V. WulfmeyerInstitute for Physics and Meteorology,University of HohenheimCo-reviewer: Prof. Dr. G. HuberInstitute for Laser Physics,University of HamburgAdditional examiner: Prof. Dr. K. JetterInstitute for AppliedMathematics and Statistics,University of HohenheimDean: Prof. Dr. H. BreerFaculty of Natural Sciences,University of HohenheimAbstract4+A gain switchedtunable Cr :YAGlaser was developedusing a Q-switchedflash-lamp–pumped Nd:YAG pump laser at 10Hz. A vacuum spatial filter (VSF) wasdesigned in order to filter the “hot spots” of the pump beam profile. As a result ofapplyingtheVSF,anearlyGaussian-shaped beamprofilewasachievedwhichenabled4+safe pumping of the Cr :YAG crystal with pulse energies in excess of 100mJ.

Sujets

• Physik

Informations

• Publié par: universitat_hohenheim
• Publié le: 01 janvier 2008
• Nombre de lectures: 21
• Poids de l'ouvrage: 4 Mo

Extrait

Developmentofaneye-safesolid-state
tunablelasertransmitteraround1.45µm
basedonCr4+:YAGcrystalforlidar
applications

DissertationzurErlangungdesDoktorgrades
derNaturwissenschaften(Dr.rer.nat.)

Fakulta¨tNaturwissenschaften
Universita¨tHohenheim

Institutfu¨rPhysikundMeteorologie

vorgelegtvon
AnnaPetrova-Mayor

ausVratsa,Bulgarien
8002

Thisthesiswasacceptedasadoctoraldissertationinfulllmentoftherequirements
forthedegree“DoktorderNaturwissenschaften”bytheFacultyofNaturalSciences
attheUniversityofHohenheim,Stuttgart,Germanyon24October2007.

Dateoforalexamination:2April2008

Examinationcommittee:

Supervisorandreviewer:

Co-reviewer:

Additionalexaminer:

eD:na

Prof.Dr.V.Wulfmeyer
InstituteforPhysicsandMeteorology,
UniversityofHohenheim
Prof.Dr.G.Huber
InstituteforLaserPhysics,
UniversityofHamburg
Prof.Dr.K.Jetter
InstituteforAppliedMathematicsandStatistics,
UniversityofHohenheim
Prof.Dr.H.Breer
FacultyofNaturalSciences,
UniversityofHohenheim

Abstract

AgainswitchedtunableCr4+:YAGlaserwasdevelopedusingaQ-switchedash-
lamp–pumpedNd:YAGpumplaserat10Hz.Avacuumspatiallter(VSF)was
designedinordertolterthe“hotspots”ofthepumpbeamprole.Asaresultof
applyingtheVSF,anearlyGaussian-shapedbeamprolewasachievedwhichenabled
safepumpingoftheCr4+:YAGcrystalwithpulseenergiesinexcessof100mJ.An
extensiveexperimentaloptimizationoftheeciencyofthewavelengthconverterwas
performed.Amaximumoutputenergyof7mJat1430–1450nm,corresponding
to7%conversioneciency(withregardtoabsorbedpumpenergy),andapulse
durationof30–35nswereobtainedwitha25-cm-longstableresonator.Tunability
intherange1350–1500nmandspectrallinewidthof200GHzweredemonstrated
usinga3-platebirefringentlter.Thelaserwasmultimodewithaat-topproleand
sucientlygoodM24.
Theperformanceandsizeofthelaserareacceptableforuseinalaboratory-
basednon-scanninglidarsystemifanarrow-bandbirefringentlterisinstalled.In
ordertoemployascanningmobilelidar,highpulsefrequency(100Hz)ofthepump
laserfortheCr4+:YAGlaserisrequired.Thetunabilitypermitstheimprovementof
thelasertransmitterforwater-vaporDIALmeasurementsaton-linewavelengthsof
approximately1459nmor1484nmifinjection-seedingisapplied.

i

Zusammenfassung
Eingain-geschalteter,abstimmbarerCr4+:YAGWellenla¨ngenkonverterwurdeent-
wickelt.Erwurdemiteinemgu¨tegeschaltetenblitzlampengepumptenNd:YAG-Laser
miteinerRepetitionsratevon10HzundeinerPulsdauervon6–8gepumpt.Dieses
SystemisteinersterSchrittzurEntwicklungeinesaugensicherenWasserdampf-DIAL-
Systemsbei1459nmund1484nm.EinVakuum-Raumlter(VRF)wurdeaufgebaut,
umdieHotSpotsimPumpstrahlpro