PREFACE ...................................................... vii
ACKNOWLEDGEMENTS ............................................... ix
LIST OF ABBREVIATIONS ........................................ xvii
1 INTRODUCTION ............................................... 1
2 MICRO-OPTICS ............................................... 3
2.1 The concept of microoptics ................................. 3
2.2 Microoptics and macrooptics ................................ 6
2.2.1 Scaling laws for a size reduction ................... 6
2.2.2 Diffraction and Fresnel number ...................... 7
2.3 Types of microoptical components ........................... 9
2.4 Refractive microoptics .................................... 11
2.4.1 Specific properties of refractive microoptical
components ......................................... 11
2.4.2 Gradient index lenses .............................. 12
2.4.3 Spherical surface relief lenses .................... 13
2.4.4 Fresnel lenses ..................................... 17
2.4.5 Fabrication of refractive components ............... 18
2.5 Reflective microoptics .................................... 19
2.6 Diffractive microoptics ................................... 21
2.7 Hybrid microoptics ........................................ 23
2.8 Replication and structure transfer ........................ 25
2.9 Specific properties of array structures ................... 26
2.9.1 Types and general features of microoptical array
structures ......................................... 26
2.9.2 Fill factor, efficiency and symmetry ............... 27
2.9.3 Spatial frequencies and Fresnel numbers ............ 29
2.9.4 Cross-talk and self-imaging effects ................ 30
2.9.5 Wavefront detection with array components .......... 32
2.9.6 Gabor superlens .................................... 34
2.10 Stacked and planar microoptics ............................ 35
2.11 Problems and trends ....................................... 35
3 THIN-FILM OPTICS .......................................... 39
3.1 The concept of thin-film optics ........................... 39
3.2 Single transparent layer on substrates .................... 39
3.2.1 Uniform Fabry-Perot etalon at monochromatic
illumination ....................................... 40
3.2.2 Fabry-Perot etalon of space-variant thickness at
monochromatic illumination ......................... 44
3.2.3 Fabry-Perot etalon of space-variant thickness at
polychromatic illumination ......................... 45
3.2.4 Transmission of ultrashort pulses through plane-
parallel etalon structures ......................... 47
3.2.5 Quarter-wave layers and half-wave layers at
monochromatic illumination ......................... 48
3.2.6 Admittance of absorbing layers at optical
frequencies ........................................ 49
3.3 Dielectric multilayer structures .......................... 51
3.3.1 The multilayer approach ............................ 51
3.3.2 Method of characteristic matrices .................. 51
3.3.3 Dispersion management by layer stacks of adapted
spectral phases .................................... 53
3.3.4 Diffraction management by layer stacks of
spatially variable reflectance ..................... 54
3.4 Metal and metal-dielectric coatings ....................... 56
3.4.1 Single reflecting metal layers ..................... 56
3.4.2 Metal-dielectric layers as Gires-Tournois
interferometer structures .......................... 56
3.5 Problems and trends ....................................... 57
4 THIN-FILM MICROOPTICS ..................................... 59
4.1 The concept of thin-film microoptics ...................... 59
4.2 Techniques for the fabrication of structured thin films:
from macroscopic to microscopic scale ..................... 60
4.2.1 Subtractive and modifying techniques ............... 60
4.2.2 Uniformity and nonuniformity of deposited layers ... 61
4.2.3 Separately rotating masks for structured light
exposure and vapor deposition ...................... 62
4.2.4 Fixed thick shadow masks and extended sputtering
sources ............................................ 63
4.2.5 Fixed thin circular shadow masks rotating with
the substrate ...................................... 64
4.2.6 Thick shadow masks fixed at the substrates in a
rotating system with point source .................. 64
4.2.7 Deposition of arrays of microoptical components
with miniaturized shadow masks ..................... 65
4.2.8 Simulation of the deposition through thick shadow
masks fixed on a substrate in a system with
planetary rotation ................................. 67
4.3 Specific properties of thin-film microoptical components .. 71
4.3.1 Specific advantages of thin-film deposition
technique with shadow masks ........................ 71
4.3.2 Specific advantages of thin-film microoptical
design ............................................. 71
4.3.3 Thin-film microoptics on substrates: Specific
properties and design constraints .................. 73
4.3.4 Contact angle and maximum angle of incidence of
thin-film microlenses .............................. 78
4.4 Types of thin-film microoptical components ................ 78
4.5 Fabrication of thin-film microoptics with shadow masks .... 80
4.5.1 Vacuum deposition with planetary rotation and
shadow masks ....................................... 80
4.5.2 Types of shadow masks for the deposition of thin-
film microstructures ............................... 81
4.5.3 Generation of arrays of high fill factors with
the method of crossed deposition ................... 83
4.5.4 Wire-grid masks .................................... 85
4.5.5 Deposition of nonspherical elements with slit and
hole array masks of conical apertures .............. 88
4.5.6 Generation of arrays of high fill factors and
parabolic profiles with mesh-shaped masks .......... 93
4.6 Pre-processing of polymer substrates for improving the
adhesion of thin-film microoptics ......................... 95
4.7 Multilayer and compound microoptics ....................... 98
4.7.1 Multilayer microoptics ............................. 98
4.7.2 Metal-dielectric structures ........................ 99
4.8 Structure transfer of thin-film microoptical components
by reactive ion etching .................................. 103
4.9 Nanolayer microoptic ..................................... 105
4.10 VUV-capable transparent thin-film microoptics ............ 107
4.11 Problems and trends ...................................... 109
5 CHARACTERIZATION OF THIN-FILM MICROOPTICS ................ 111
5.1 Specific measuring problems .............................. 111
5.2 Interferometric characterization of thin-film microlens
arrays ................................................... 112
5.2.1 Phase shift interferometer ........................ 112
5.2.2 Characterization of shape distribution and
periodicity of microlens arrays ................... 113
5.2.3 Optical functions of thin-film microlens arrays ... 116
5.3 Reflectance mapping of multilayer microoptics ............ 119
5.3.1 Spatially resolved measurement of specular
reflectance ....................................... 119
5.3.2 Spatial reflectance mapping with angular
resolution ........................................ 123
5.4 Near field propagation measurements ...................... 123
6 SPATIAL BEAM SHAPING WITH THIN-FILM MICROOPTICS .......... 125
6.1 Hybrid microoptics for improved efficiency of laser
diode collimation ........................................ 125
6.1.1 Motivation and basic concepts ..................... 125
6.1.2 Slow-axis collimation with compact systems of
cylindrical microlenses ........................... 128
6.1.3 Angular-adapted micro-gradient AR coatings ........ 130
6.2 Mode-selection in laser resonators ....................... 133
6.2.1 Stability management of compact solid-state
laser resonators with rmcro-mirrors ............... 133
6.2.2 Talbot resonators with micro-mirror arrays ........ 134
6.2.3 Mode stabilization in laser diode MOPA-systems
with external resonator for second harmonic
generation ........................................ 137
6.3 Generation of Bessel-like nondiffracting beams ........... 139
6.3.1 Nondiffracting beams .............................. 139
6.3.2 Bessel-like beams ................................. 141
6.3.3 Generation of arrays of microscopic Bessel-like
beams with thin-film axicons ...................... 143
6.3.4 Spatial self-reconstruction of Bessel-like beams .. 146
6.3.5 Self-apodized truncation of Bessel beams as
a first way to shape needle beams ................. 147
6.3.6 Ultrafiat thin-film axicons of extremely small
conical angles as a second way to generate
needle beams ...................................... 152
6.4 Shack-Hartmann wavefront sensing at extreme laser
parameters with Bessel-like beams ........................ 155
6.4.1 Particular features of Shack-Hartmann sensors
with Bessel-like nondiffracting beams ............. 155
6.4.2 Transmissive and reflective setups with
angular-tolerant thin-film microaxicons ........... 157
6.5 VUV laser beam array generation and multichannel
materials processing ..................................... 160
6.5.1 VUV beam array generation with thin-film
microoptics ....................................... 160
6.5.2 Beam cleaning by absorption ....................... 162
6.5.3 VUV materials processing with thin-film
microoptics ....................................... 163
7 SPATIO-TEMPORAL BEAM SHAPING AND CHARACTERIZATION OF
ULTRASHORT-PULSE LASERS .................................. 167
7.1 Motivation ............................................... 167
7.2 Coherence mapping ........................................ 168
7.2.1 Microoptical approaches based on multichannel
interferometry .................................... 168
7.2.2 Coherence mapping with thin-film Fabry-Perot
arrays ............................................ 171
7.2.3 Coherence mapping with arrays of Bessel-like
beams ............................................. 172
7.2.4 Decoding of axial coherence information with
arrays of Bessel-like beams ....................... 176
7.2.5 Coherence mapping with the Talbot effect .......... 176
7.3 Spatio-temporal autocorrelation .......................... 179
7.3.1 Processing and characterization of ultrashort
optical pulses .................................... 179
7.3.2 Concept of the collinear matrix autocorrelator
based on arrays of Bessel-like beams .............. 180
7.3.3 Transversal autocorrelation information in
Bessel-like beams ................................. 182
7.3.4 Wavefront autocorrelation experiments ............. 183
7.4 Hyperspectral sensing of polychromatic wavefronts ........ 188
7.4.1 Prospects for a spatially-resolved spectral
phase measurement ................................. 188
7.4.2 Hyperspectral Shack-Hartmann wavefront sensor
with graxicon arrays .............................. 190
7.5 Generation of optical spatio-temporal X-pulses with
thin-film structures ..................................... 193
7.5.1 X-waves and X-pulses as spectral interference
phenomena in spatio-temporal domain ............... 193
7.5.2 Generation and direct detection of arrayed
microscopic-size pulsed optical Bessel-like
X-waves and single macroscopic Bessel-Gauss
X-pulses .......................................... 194
7.6 Self-apodized truncation of ultrashort and
ultrabroadband Bessel pulses ............................. 196
7.6.1 Spatial propagation of ultrashort-pulsed and
ultrabroadband truncated Bessel-like beams
generated with thin-film beam shapers ............. 197
7.6.2 Spatio-spectral and spatio-temporal transfer of
ultrashort-pulsed and ultrabroadband truncated
Bessel-Gauss beams ................................ 199
7.6.3 Comparison to ultrashort-pulsed Gaussian beams .... 201
7.7 Spatio-temporal self-reconstruction and nondiffracting
images ................................................... 202
7.7.1 Self-reconstruction and spatio-temporal
information ....................................... 202
7.7.2 Nondiffracting images ............................. 203
OUTLOOK ....................................................... 205
REFERENCES .................................................... 207
FIGURE CREDITS ................................................ 253
GLOSSARY ...................................................... 255
INDEX ......................................................... 279
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