Compact Blue-Green Lasers

553 Pages·2003·5.895 MB·English

by  W. P. Risk, T. R. Gosnell, A. V. Nurmikko

COMPACT BLUE-GREEN LASERS
This book describes the theory and practical implementation of three techniques
for the generation of blue-green light: nonlinear frequency conversion of infrared
lasers,upconversionlasers,andwide-bandgapsemiconductordiodelasers.
The book begins with a discussion of the various applications that have driven
thedevelopmentofcompactsourcesofblue-greenlight.Part1thendescribesap-
proachestoblue-greenlightgenerationthatexploitsecond-ordernonlinearoptics,
includingsingle-pass,intracavity,resonator-enhancedandguided-wavesecondhar-
monicgeneration.Part2,concernedwithupconversionlasers,investigateshowthe
energyofmultipleredorinfraredphotonscanbecombinedtodirectlypumpblue-
greenlasertransitions.Thephysicalbasisofthisapproachisthoroughlydiscussed
andbothbulk-opticandfiber-opticimplementationsaredescribed.Part3describes
wide-bandgapblue-greensemiconductordiodelasers,implementedinbothII–VI
and III–V materials. The concluding chapter reflects on the progress in develop-
ingtheselasersandusingtheminpracticalapplicationssuchashigh-densitydata
storage,colordisplays,reprographics,andbiomedicaltechnology.
CompactBlue-GreenLasersprovidesthefirstcomprehensive,unifiedtreatment
ofthissubjectandissuitableforuseasanintroductorytextbookforgraduate-level
coursesorasareferenceforacademicsandprofessionalsinoptics,appliedphysics,
andelectricalengineering.
william p. risk received the PhD degree from Stanford University in 1986. He
joined the IBM Corporation in 1986 as a Research Staff Member at the Almaden
ResearchCenterinSanJose,CA.Hisworkthereforseveralyearswasconcerned
with the development of compact blue-green lasers for high-density optical data
storage.Morerecently,hehasbeenactiveintheemergingfieldofquantuminforma-
tion,andnowmanagestheQuantumInformationGroupattheAlmadenResearch
Center. Dr Risk has authored or coauthored some 70 publications in technical
journalsandconferenceproceedingsandholdsseveralpatents.
timothy r. gosnell has been a technical staff member at Los Alamos National
LaboratorysincereceivinghisPhDinphysicsfromCornellUniversityin1986.He
haspursuedresearchactivitiesintheareasofbiophysics,nonlinearoptics,ultrafast
laserphysicsandapplications,upconversionlasers,andmostrecentlyinthelaser
coolingofsolidsandapplicationsofmagneticresonancetosingle-spindetection.
He is the author of over 40 scientific papers and editor of several books in these
fields.Inadditiontohisresearchworkinthepublicsector,DrGosnellhasrecently
enteredtheprivatesectorasaseniorscientistforPixonLLC,aninformaticsstartup
company that applies information theory and advanced statistical techniques to
imageprocessingandtheanalysisofcomplexalgebraicsystems.
arto v. nurmikko received his PhD degree in electrical engineering from the
UniversityofCalifornia,Berkeley.FollowingapostdoctoralpositionattheMassa-
chusettsInstituteof Technology,hejoinedBrownUniversityFacultyof Electrical
Engineeringin1975.HeispresentlytheL.HerbertBallouUniversityProfessorof
Engineering and Physics, as well as the Director of the Center for Advanced Ma-
terialsResearch.ProfessorNurmikkoisaninternationalauthorityonexperimental
condensedmatterphysicsandquantumelectronics,particularlyontheuseoflaser-
basedmicroscopiesandadvancedspectroscopyforbothfundamentalandapplied
purposes. His current interests are focused on optoelectronic material nanostruc-
turesandtheirdevicescience.ProfessorNurmikkoistheauthorofapproximately
270scientificjournalpublications.
COMPACT BLUE-GREEN LASERS
W. P. RISK
T. R. GOSNELL
A. V. NURMIKKO
  
Cambridge, New York, Melbourne, Madrid, Cape Town, Singapore, São Paulo
Cambridge University Press
The Edinburgh Building, Cambridge  , United Kingdom
Published in the United States by Cambridge University Press, New York
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© Cambridge University Press 2003
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without the written permission of Cambridge University Press.
First published in print format 2003
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ISBN-13 978-0-521-62318-6 hardback
ISBN-10 0-521-62318-9 hardback
ISBN-13 978-0-521-52103-1 paperback
ISBN-10 0-521-52103-3 paperback
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Contents
Preface page xi
1 Theneedforcompactblue-greenlasers 1
1.1 Ashorthistoricaloverview 1
1.2 Applicationsforcompactblue-greenlasers 3
1.2.1 Opticaldatastorage 3
1.2.2 Reprographics 5
1.2.3 Colordisplays 6
1.2.4 Submarinecommunications 8
1.2.5 Spectroscopicapplications 12
1.2.6 Biotechnology 14
1.3 Blue-greenandbeyond 17
References 17
Part1 Blue-greenlasersbasedonnonlinearfrequencyconversion 20
2 Fundamentalsofnonlinearfrequencyupconversion 20
2.1 Introduction 20
2.2 BasicprinciplesofSHGandSFG 21
2.2.1 Thenatureofthenonlinearpolarization 21
2.2.2 Frequenciesoftheinducedpolarization 23
2.2.3 Thedcoefficient 28
2.2.4 Thegeneratedwave 30
2.2.5 SHGwithmonochromaticwaves 34
2.2.6 Multi-longitudinalmodesources 34
2.2.7 Pumpdepletion 38
2.3 Spatialconfinement 43
2.3.1 Boyd–KleinmananalysisforSHGwithcircular
gaussianbeams 43
2.3.2 Guided-waveSHG 51
v
vi Contents
2.4 Phasematching 56
2.4.1 Introduction 56
2.4.2 Birefringentphasematching 57
2.4.3 Quasi-phasematching(QPM) 71
2.4.4 Waveguidephasematching 90
2.4.5 Otherphasematchingtechniques 97
2.4.6 Summary 101
2.5 Materialsfornonlineargenerationofblue-greenlight 101
2.5.1 Introduction 101
2.5.2 Lithiumniobate(LN) 101
2.5.3 Lithiumtantalate(LT) 108
2.5.4 Potassiumtitanylphosphate(KTP) 110
2.5.5 Rubidiumtitanylarsenate(RTA) 115
2.5.6 OtherKTPisomorphs 119
2.5.7 Potassiumniobate(KN) 119
2.5.8 Potassiumlithiumniobate(KLN) 121
2.5.9 Lithiumiodate 123
2.5.10 Betabariumborate(BBO)andlithium
borate(LBO) 124
2.5.11 Othermaterials 126
2.6 Summary 130
References 130
3 Single-passSHGandSFG 149
3.1 Introduction 149
3.2 Directsingle-passSHGofdiodelasers 151
3.2.1 Earlyexperimentswithgain-guidedlasers 151
3.2.2 Earlyexperimentswithindex-guidedlasers 154
3.2.3 High-powerindex-guidednarrow-stripelasers 156
3.2.4 Multiple-stripearrays 157
3.2.5 Broad-arealasers 160
3.2.6 Masteroscillator–poweramplifier(MOPA)
configurations 161
3.2.7 Angled-gratingdistributedfeedback(DFB)
lasers 169
3.3 Single-passSHGofdiode-pumpedsolid-statelasers 170
3.3.1 Frequency-doublingof1064-nmNd:YAG
lasers 177
3.3.2 Frequency-doublingof946-nmNd:YAGlasers 177
3.3.3 Sum-frequencymixing 178
3.4 Summary 178
References 179
Contents vii
4 Resonator-enhancedSHGandSFG 183
4.1 Introduction 183
4.2 Theoryofresonatorenhancement 187
4.2.1 Theimpactofloss 189
4.2.2 Impedancematching 191
4.2.3 Frequencymatching 193
4.2.4 Approachestofrequencylocking 194
4.2.5 Modematching 207
4.3 Otherconsiderations 213
4.3.1 Temperaturelocking 213
4.3.2 Modulation 214
4.3.3 Bireflectioninmonolithicringresonators 215
4.4 Summary 220
References 220
5 IntracavitySHGandSFG 223
5.1 Introduction 223
5.2 TheoryofintracavitySHG 224
5.3 The“greenproblem” 229
5.3.1 Theproblemitself 229
5.3.2 Solutionstothe“greenproblem” 231
5.3.3 Single-modeoperation 235
5.4 BluelasersbasedonintracavitySHGof946-nm
Nd:YAGlasers 245
5.5 IntracavitySHGofCr:LiSAFlasers 249
5.6 Self-frequency-doubling 250
5.6.1 Nd:LN 251
5.6.2 NYAB 252
5.6.3 Periodically-poledmaterials 253
5.6.4 Othermaterials 253
5.7 Intracavitysum-frequencymixing 253
5.8 Summary 255
References 256
6 Guided-waveSHG 263
6.1 Introduction 263
6.2 Fabricationissues 264
6.3 Integrationissues 269
6.3.1 Feedbackandfrequencystability 270
6.3.2 Polarizationcompatibility 276
6.3.3 Coupling 282
6.3.4 Controlofthephasematchingcondition 283
6.3.5 Extrinsicefficiencyenhancement 284
viii Contents
6.4 Summary 286
References 287
Part2 Upconversionlasers:Physicsanddevices 292
7 Essentialsofupconversionlaserphysics 292
7.1 Introductiontoupconversionlasersandrare-earth
opticalphysics 292
7.1.1 Overviewofrare-earthspectroscopy 295
7.1.2 Qualitativefeaturesofrare-earthspectroscopy 296
7.2 Elementsofatomicstructure 303
7.2.1 Theeffectivecentralpotential 303
7.2.2 Electronicstructureofthefreerare-earthions 306
7.3 TheJudd–Ofeltexpressionforopticalintensities 324
7.3.1 Basicformulation 325
7.3.2 TheJudd–Ofeltexpressionfortheoscillator
strength 329
7.3.3 Selectionrulesforelectricdipoletransitions 336
7.4 Nonradiativerelaxation 338
7.5 Radiationlessenergytransfer 341
7.6 Mechanismsofupconversion 345
7.6.1 Resonantmulti-photonabsorption 345
7.6.2 Cooperativeupconversion 348
7.6.3 Rateequationformulationofupconversionby
radiationlessenergytransfer 357
7.6.4 Thephotonavalanche 360
7.7 Essentialsoflaserphysics 363
7.7.1 Qualitativepicture 364
7.7.2 Rateequationsforcontinuous-wave
amplificationandlaseroscillation 365
7.8 Summary 382
References 383
8 Upconversionlasers 385
8.1 Historicalintroduction 385
8.2 Bulkupconversionlasers 397
8.2.1 UpconversionpumpedEr3+ infraredlasers 398
8.2.2 Er3+ visibleupconversionlasers 410
8.2.3 Tm3+ upconversionlasers 420
8.2.4 Pr3+ upconversionlasers 424
8.2.5 Nd3+ upconversionlasers 425
8.3 Upconversionfiberlasers 427
8.3.1 Er3+ fiberlasers;4S3/2 → 4I15/2 transition
at556nm 433
Contents ix
8.3.2 Tm3+ fiberlasers 436
8.3.3 Pr3+ fiberlasers 445
8.3.4 Ho3+ fiberlasers,5S → 5I transition
2 8
at∼550nm 455
8.3.5 Nd3+ fiberlasers 457
8.4 Prospects 458
References 460
Part3 Blue-greensemiconductorlasers 468
9 Introductiontoblue-greensemiconductorlasers 468
9.1 Overview 468
9.2 Overviewofphysicalpropertiesofwide-bandgap
semiconductors 470
9.2.1 Latticematching 470
9.2.2 Epitaxiallateralovergrowth(ELOG) 472
9.2.3 Basicphysicalparameters 474
9.3 Dopinginwide-gapsemiconductors 475
9.4 Ohmiccontactsforp-typewide-gapsemiconductors 478
9.4.1 Ohmiccontactstop-AlGaInN 479
9.4.2 Newapproachestop-contacts 481
9.4.3 Ohmiccontactstop-ZnSe:bandstructure
engineering 482
9.5 Summary 484
References 484
10 Devicedesign,performance,andphysicsofopticalgainofthe
InGaNQWvioletdiodelasers 487
10.1 Overviewofblueandgreendiodelaserdeviceissues 487
10.2 TheInGaNMQWvioletdiodelaser:Designand
performance 488
10.2.1 Layereddesignandepitaxialgrowth 488
10.2.2 Diodelaserfabricationandperformance 496
10.3 PhysicsofopticalgainintheInGaNMQWdiodelaser 501
10.3.1 OntheelectronicmicrostructureofInGaNQWs 506
10.3.2 Excitoniccontributionsingreen-blue
ZnSe-basedQWdiodelasers 509
10.4 Summary 513
References 513
11 Prospectsandpropertiesforvertical-cavitybluelightemitters 517
11.1 Background 517
11.2 Opticalresonatordesignandfabrication:Demonstration
ofoptically-pumpedVCSELoperationinthe
380–410-nmrange 518