Lasers: Basics, Advances and Applications

507 Pages·2018·16.51 MB·English

by  Hans Joachim Eichler

Springer Series in Optical Sciences 220
Hans Joachim Eichler · Jürgen Eichler 
Oliver Lux
Lasers
Basics, Advances and Applications
Springer Series in Optical Sciences
Volume 220
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Ferenc Krausz, Ludwig-Maximilians-Universität München, Garching, Germany
Barry R. Masters, Cambridge, USA
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ü
Hans Joachim Eichler J rgen Eichler
(cid:129)
Oliver Lux
Lasers
Basics, Advances and Applications
123
Hans JoachimEichler Oliver Lux
Institut für OptikundAtomare Physik Institute of Atmospheric Physics
Technische UniversitätBerlin German Aerospace Center(DLR)
Berlin, Germany Weßling, Germany
JürgenEichler
BeuthHochschule für Technik
Berlin, Germany
ISSN 0342-4111 ISSN 1556-1534 (electronic)
SpringerSeries inOptical Sciences
ISBN978-3-319-99893-0 ISBN978-3-319-99895-4 (eBook)
https://doi.org/10.1007/978-3-319-99895-4
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Preface
This book provides a comprehensive overview of various laser sources and their
applicationsinthefieldsofscience,industry,andmedicine.Afteranintroductionto
thebasicsoflaserphysics,differentlasertypesandmaterialsaresummarizedinthe
context of a historical survey, outlining the development of laser technology since
the first experimental demonstration in 1960. Gas lasers and a wide range of
solid-state and semiconductor lasers are described with particular attention to
high-power sources. The monograph predominantly focuses on the laser materials
while electrical power supplies and mechanical engineering are only sketched.
Laserbeampropagationbothinfree-spaceandopticalfibers,differentresonator
designs as well as the functionality of various optical and opto-electronic laser
components are treated from an engineering point of view. Laser modulation and
pulse generation are reviewed leading to the discussion of extreme laser sources
with ultra-short pulse widths below femtoseconds and pulse peak powers greater
than petawatts. The book also describes techniques for nonlinear frequency con-
version extendingthe range of available laser frequencies into the THz- and X-ray
region.
Finally,thegreatimportanceoflasersineverydaylifeandmoderntechnologyas
well as its potential for future developments is discussed. The focus is on
biomedicalandmaterialprocessingapplications,butprestigiouslarge-scaleprojects
forgravitationalwavedetection,laserfusion,andspacebornelidarmissionsarealso
presented.
The book gives a broad and up-to-date coverage of laser photonics and
opto-electronics, providing main results and recent advancements rather than
in-depth theoretical treatment. Following in the steps of eight German and two
Russian editions, this new English edition is targeted not only at university stu-
dents, physicists, and engineers but also at any scientist and professional applying
lasers in biomedicine, material processing, consumer products, and their
manufacturing.
We acknowledge the scientific and technical support of recent and present
members of the Laser Group at the Technische Universität Berlin, C. Junghans,
J.Laufer,S.G.Strohmaier,M.H.Azhdast,andI.Usenovaswellasrepresentatives
v
vi Preface
oftheworldwidelasercommunity,V.Artyushenko,ARTphotonicsGmbH,Berlin,
Germany, C. Ascheron, Springer Verlag, Heidelberg, Germany, W. Gries, NKT
Photonics,Copenhagen, Denmark, W.Bohn,German Aerospace Center, Stuttgart,
Germany, D. A. Pintsov, San Diego, USA, and M. Schulze, Coherent Inc., Santa
Clara, USA.
Berlin, Germany Hans Joachim Eichler
October 2018 Jürgen Eichler
Oliver Lux
Contents
Part I Emission of Light and Laser Fundamentals
1 Light, Atoms, Molecules, Solids . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1 Characteristics of Light: Waves and Photons . . . . . . . . . . . . . . 3
1.2 Atoms: Energy Levels. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
1.3 Many-Electron Atoms. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
1.4 Molecules. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
1.5 Energy Levels in Solids . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
1.6 Energy Bands in Semiconductors. . . . . . . . . . . . . . . . . . . . . . . 20
Further Reading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
2 Absorption and Emission of Light . . . . . . . . . . . . . . . . . . . . . . . . . 29
2.1 Absorption . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
2.2 Spontaneous Emission. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
2.3 Light Amplification by Stimulated Emission. . . . . . . . . . . . . . . 32
2.4 Linewidth. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
2.5 Population Inversion, Gain Depletion and Saturation. . . . . . . . . 39
2.6 Light Emission by Accelerated Electrons . . . . . . . . . . . . . . . . . 41
2.7 Basic Laser Setup. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
2.8 Temporal Emission Behavior. . . . . . . . . . . . . . . . . . . . . . . . . . 45
Further Reading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
3 Laser Types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
3.1 Wavelengths and Output Powers . . . . . . . . . . . . . . . . . . . . . . . 53
3.2 Tunable Lasers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
3.3 Frequency-Stable Lasers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59
3.4 High-Power Lasers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59
3.5 Ultra-short Light Pulses. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60
3.6 Beam Parameters and Stability. . . . . . . . . . . . . . . . . . . . . . . . . 61
Further Reading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62
vii
viii Contents
Part II Gas and Liquid Lasers
4 Laser Transitions in Neutral Atoms . . . . . . . . . . . . . . . . . . . . . . . . 65
4.1 Helium–Neon Lasers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65
4.2 Atomic Metal Vapor Lasers. . . . . . . . . . . . . . . . . . . . . . . . . . . 71
4.3 Iodine Lasers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74
Further Reading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76
5 Ion Lasers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77
5.1 Lasers for Short Wavelengths . . . . . . . . . . . . . . . . . . . . . . . . . 77
5.2 Noble Gas Ion Lasers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79
5.3 Metal Vapor Ion Lasers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83
Further Reading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88
6 Infrared Molecular Gas Lasers. . . . . . . . . . . . . . . . . . . . . . . . . . . . 89
6.1 Far-Infrared Lasers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89
6.2 CO Lasers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92
2
6.3 CO Lasers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104
6.4 HF Lasers, Chemical Lasers . . . . . . . . . . . . . . . . . . . . . . . . . . 106
Further Reading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110
7 Ultraviolet Molecular Gas Lasers . . . . . . . . . . . . . . . . . . . . . . . . . . 111
7.1 Nitrogen Lasers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111
7.2 Excimer Lasers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 114
Further Reading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 120
8 Dye Lasers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121
8.1 Laser Action in Dyes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121
8.2 Laser-Pumped Dye Lasers. . . . . . . . . . . . . . . . . . . . . . . . . . . . 124
8.3 Polymer and Liquid Crystal Lasers . . . . . . . . . . . . . . . . . . . . . 129
Further Reading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 130
Part III Solid-State and Semiconductor Lasers
9 Solid-State Lasers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 133
9.1 Ruby Lasers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 134
9.2 Neodymium Lasers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 138
9.3 Erbium, Holmium and Thulium Lasers. . . . . . . . . . . . . . . . . . . 147
9.4 Tunable Solid-State Lasers . . . . . . . . . . . . . . . . . . . . . . . . . . . 151
9.5 Diode Pumping and High-Power Operation . . . . . . . . . . . . . . . 158
Further Reading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 164
10 Semiconductor Lasers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 165
10.1 Light Amplification in p-n Diodes . . . . . . . . . . . . . . . . . . . . . . 168
10.2 GaAlAs and InGaAsP Lasers. . . . . . . . . . . . . . . . . . . . . . . . . . 170
10.3 Design of Diode Lasers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 172
Contents ix
10.4 Characteristics of Diode Laser Emission. . . . . . . . . . . . . . . . . . 184
10.5 Wavelength Selection and Tuning of Diode Lasers. . . . . . . . . . 189
10.6 Surface-Emitting Diode Lasers. . . . . . . . . . . . . . . . . . . . . . . . . 192
10.7 Semiconductor Lasers for the Mid-IR and THz-Region. . . . . . . 195
10.8 Ultraviolet and Visible InGaAs Lasers . . . . . . . . . . . . . . . . . . . 199
10.9 Diode Lasers for Optical Communication. . . . . . . . . . . . . . . . . 201
Further Reading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 203
Part IV Free and Guided Light Wave Propagation
11 Laser Beam Propagation in Free Space . . . . . . . . . . . . . . . . . . . . . 207
11.1 Plane and Spherical Waves, Diffraction . . . . . . . . . . . . . . . . . . 207
11.2 Gaussian Beams . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 209
11.3 Propagation of Gaussian Beams Through Lenses . . . . . . . . . . . 216
11.4 Telescopes and Spatial Frequency Filters . . . . . . . . . . . . . . . . . 219
11.5 Propagation of Multimode, Real Laser Beams . . . . . . . . . . . . . 222
Further Reading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 229
12 Optical Resonators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 231
12.1 Plane-Mirror Resonators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 231
12.2 Spherical-Mirror Resonators . . . . . . . . . . . . . . . . . . . . . . . . . . 234
12.3 Resonator Configurations and Stability. . . . . . . . . . . . . . . . . . . 238
Further Reading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 244
13 Optical Waveguides and Glass Fibers. . . . . . . . . . . . . . . . . . . . . . . 245
13.1 Optical Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 245
13.2 Planar, Rectangular and Cylindrical Waveguides . . . . . . . . . . . 248
13.3 Fiber Types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 255
13.4 Fiber Damping, Dispersion and Nonlinearities . . . . . . . . . . . . . 260
Further Reading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 266
Part V Optical Elements for Lasers
14 Mirrors. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 269
14.1 Reflection and Refraction . . . . . . . . . . . . . . . . . . . . . . . . . . . . 270
14.2 Dielectric Multilayer Mirrors . . . . . . . . . . . . . . . . . . . . . . . . . . 275
14.3 Beam Splitters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 280
14.4 Phase Conjugate Mirrors. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 281
Further Reading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 287
15 Polarization. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 289
15.1 Types of Polarization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 289
15.2 Birefringence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 291
15.3 Polarizers and Retardation Plates . . . . . . . . . . . . . . . . . . . . . . . 294
Further Reading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 298