Frontiers of Optical Spectroscopy (eBook)

CONTENTS 6
PREFACE 20
LIST OF PAST INSTITUTES 22
1. INVESTIGATING PHYSICAL SYSTEMS WITH OPTICAL SPECTROSCOPY 23
1. Introduction 23
2. Interaction of Radiation with Atoms and Molecules 24
2. LIGHT-MATTER INTERACTIONS ON THE FEMTOSECOND TIME SCALE 51
1. Light—matter interactions 51
2. Ultrafast dynamics of solids under intense photoexcitation 58
3. Nonlinear optical properties 63
4. Ultrafast Materials Science 65
5. Summary 71
3. PHOTONS AND PHOTON STATISTICS: FROM INCANDESCENT LIGHT TO LASERS 77
1. Introduction 77
2. Nature of light 77
3. Classical Description of the EMF: Waves 81
4. Quantum Theory of Light: Photons 86
5. Optical devices and measurements 97
6. Outlook 112
7. Acknowledgement 112
4. CARRIER-WAVE NONLINEAR OPTICS 115
1. Introduction 115
2. Some Aspects of Few-Cycle Laser Pulses From Mode-Locked Oscillators 117
3. How Intense is the Light Field? Rabi Energy, Ponderomotive Energy and Bloch Energy 131
4. Carrier-Wave Rabi Flopping of Electrons in Semiconductors 141
5. "Off-Resonant" Carrier-Wave Nonlinear Optics of Electrons in Semiconductors 163
6. Attosecond Pulses and Interaction of Intense Laser Fields With Atoms, Electrons and the Vacuum 175
7. Summary 192
8. Acknowledgements 193
9. References 194
10. Solutions of Exercises 198
11. Important Symbols and Constants 201
12. Appendices 203
5. CAROTENOID EXCITED STATES-PHOTOPHYSICS, ULTRAFAST DYNAMICS AND PHOTOSYNTHETIC FUNCTIONS 209
1. Introduction 209
2. Excited state structure of carotenoid molecules 210
3. Excited states of Carotenoids in Pigment Protein complexes 217
6. SPECTROSCOPY OF QUANTUM WELLS AND SUPERLATTICES 243
1. Prolog 243
2. Introduction to Electronic Properties 244
3. Quantum Wells and Superlattices 251
4. Interband Spectroscopy 255
5. Intersubband Transitions 260
6. Phonons in Bulk Semiconductors 262
7. Phonons in Superlattices 265
8. Conclusion and Outlook 270
7. LASERS FOR FRONTIER SPECTROSCOPY 273
1. Introduction 273
2. The rise of lasers 274
3. Spectroscopy with lasers 283
4. Advancements of laser and spectroscopy 292
5. Conclusions 306
8. COHERENT SPECTROSCOPY OF STRATIFIED SEMICONDUCTOR MICRO- AND NANOSTRUCTURES 311
1. Introduction [1] 311
2. Maxwell's equations [3] 312
3. Transmission and Reflectivity [3] 314
4. Multiple-beam interference [3] 315
5. Refraction and reflection at the surface of an absorptive medium 318
6. Absorptive Fabry-Perot interferometer [4] 324
7. Basic physics of microcavities [5] 324
8. Angle-dependent properties [5] 334
9. Electron envelope wavefunctions *F(z) 344
10. Acknowledgements 354
11. References 355
9. CONSEQUENCES OF EXTREME PHOTON CONFINEMENT IN MICROCAVITIES: I. ULTRA-SENSITIVE DEDECTION OF PERTURBATIONS BY BIO-MOLECULES 359
1. Introduction 360
2. Simple Considerations 361
3. Theoretical Approach 362
4. Experimental Insights which grow out of the Fig.3 365
5. First Order Perturbation Theory: Spherically Symmetric Layer 367
6. Experimental Setup 371
7. Experimental Results 373
10. LUMINESCENCE PROPERTIES OF VERY SMALL SEMICONDUCTOR PARTICLES 381
1. Introduction 381
2. Some possible application areas of very small semi-conductor quantum dots 381
3. Elementary quantum mechanics 384
4. Electrons in a Crystal 395
5. Density of states in low dimensional structures 400
6. Electrons, holes and excitons 402
7. Low dimensional structures 403
8. Quantum confinement in action 405
9. Outlook 414
10. References 414
11. AN INTRODUCTION TO THE PHYSICS OF ULTRACOLD ATOMIC GASES 417
1 Energy and length scales 418
2 Bose-Einstein condensation 422
3 Interatomic interactions 425
4 Equilibrium properties of a trapped gas 428
5 Dynamics of condensates 432
6 Potential flow and quantized vortices 436
7 Other topics 438
8 Concluding remarks 444
12. LASER COOLING AND TRAPPING OF NEUTRAL ATOMS TO ULTRALOW TEMPERATURES 449
1. Introduction 449
2. Radiative forces 451
3. Deceleration and cooling of an atomic beam 461
4. Traps for neutral atoms 467
5. Sub-Doppler laser cooling 476
6. Optical lattices 482
7. Manipulating Bose-Einstein condensates with light 490
13. ULTRAFAST STRUCTURAL DYNAMICS IN THE CONDENSED PHASE 519
1. Introduction: 519
2. Historical background: from kinetics to dynamics [4]: 520
3. Basic Quantum Mechanics 521
4. Wave packets dynamics in isolated systems: 523
5. Wave packets dynamics in solids 525
6. Wave packet dynamics in biological systems 532
7. New frontiers of ultrafast structural dynamics 535
14. LANTHANIDE SERIES SPECTROSCOPY UNDER EXTREME CONDITION 543
1. Introduction 543
2. Absorption Saturation 544
3. Amplified Spontaneous Emission 546
4. Energy Transfer 547
5. Self Quenching 555
6. Up Conversion 557
7. Excited State Absorption 558
8. Summary 560
9. References 560
15. EXCITONIC BOSE-EINSTEIN CONDENSATION VERSUS ELECTRON-HOLE PLASMA FORMATION 561
1. Introduction 561
2. The electron-hole Plasma 563
3. Excitonic Bose-Einstein Condensation and Superfluidity 575
4. Conclusion and Outlook 588
16. DYNAMICS OF SOLID-STATE COHERENT LIGHT SOURCES 593
1. Introduction 593
2. Spectroscopic Processes of Rare-Earth Ions in Solid-State Laser Materials 593
3. Upconversion Dynamics 599
4. Impact of Energy-Transfer Upconversion on Solid-State Laser Performance 604
5. Conclusions 607
17. SOME NOVEL ASPECTS OF INTRAMOLECULAR ELECTRONIC ENERGY TRANSFER PROCESSES 613
1.Introduction 613
2. The naphthalene - anthracene bichromophoric molecular system 618
18. STIMULATED RAMAN SCATTERING SPECTROSCOPY OF FRONTIER NONLINEAR-LASER MATERIALS: ORGANIC CRYSTALS AND NANOCRYSTALLINE CERAMICS 641
1. Introduction 641
2. The steady-state stimulated Raman scattering 643
3. Stimulated Raman spectroscopy of nonlinear-laser organic crystals and nanocrystalline ceramics 646
4. Conclusion 649
19. STRANGE PROPERTIES OF QUANTUM SYSTEMS AND POSSIBLE INTERPRETATIONS 669
1. Introduction 669
2. Resume1 of the main ingredients of Quantum Mechanics 670
3. Entangled states and the EPR argument 675
4. Bell's inequality 678
5. Experimental tests 681
6. An application of the EPR theorem 682
7. Macroscopic quantum superposition and the measurement problem 684
20. MODULATION SPECTROSCOPY REVISITED 691
1. Introduction 691
2. The Dielectric Function and Reflectivity 692
3. Modulation Methods 698
4. Some Applications 702
21. ADVANCES IN SOLID STATE LASERS AT NASA LANGLEY RESEARCH CENTER 709
22. COMBINATORIAL CHEMISTRY TO GROW SINGLE CRYSTALS AND ANALYSIS OF CONCENTRATION QUENCHING PROCESS: APPLICATION TO Yb3+-DOPED LASER CRYSTALS. 711
1.Introduction 711
2. Fibre crystal growth 713
3. Illustration of our approach for Yb -doped crystals 715
4. Analysis of concentration quenching processes 723
5.Model to interpret radiation self-trapping and self-quenching mechanisms in Yb3+. 733
6. Conclusion 735
23. TABLE-TOP SOFT X-RAY LASERS AND THEIR APPLICATIONS 737
1. Introduction 737
2. Pumping Techniques 738
24. RARE EARTH ION DOPED CERAMIC LASER MATERIALS 743
1. Introduction 743
2. Nd doped Ceramic YAG 743
3. New Lead-based Ceramic Laser Materials 746
4. Summary 753
25. SHORT SEMINARS 755
CONFOCAL FLUORESCENCE AND RAMAN MICROSCOPY OF FEMTOSECOND LASER-MODIFIED FUSED SILICA 755
OPTICAL CHARACTERIZATION OF QUANTUM DOTS 755
NEW PHOSPHORS FOR ULTRAVIOLET EXCITATION 756
MAIN TOPICS OF INTERESTS IN THE AREA OF LUMINESCENCE MATERIALS 756
INTERACTION OF FEMTOSECOND PULSES WITH TRANSPARENT MATERIALS 757
ULTRAFAST PHASE TRANSITIONS IN SOLIDS 757
RELAXATION PATHWAYS FROM ELECTRONIC EXCITED STATES OF OXYGEN DEFICIENT CENTERS IN GE-DOPED SILICA 758
DETECTING QUANTUM SIGNATURES IN THE DYNAMICS OF TRAPPED IONS 759
NON-EQUILIBRIUM POLARIZATION IN DIELECTRICS AND RELATED PHENOMENA 760
OPTICAL TRANSITIONS IN QUANTUM NANOSTRUCTURES BASED ON IONIC MATERIALS 761
LEDS MAKE THINGS BETTER 762
26. POSTERS 763
PHOTOREFLECTANCE AND LUMINESCENCE MEASUREMENTS OF GAINNAS/GAAS MULTIPLE QUANTUM WELL STRUCTURES 763
SELF-CONSISTENT CALCULATION OF GROUND AND EXCITED ENERGY LEVELS OF A DOPED QUANTUM DOT BY A QUANTUM GENERIC ALGORITHM 763
THE WIRES DIRECTION PHOTOCONDUCTIVITY OF GAAS/ALGAAS QUANTUM WIRES MEASURED ALONG 764
HIGH EXCITATION SPECTROSCOPY OF ZnO 764
PROPERTIES OF PECVD a-SiOx:H FILMS 765
OPTICAL INVESTIGATION OF SPIN INJECTION INTO OPTICALLY ACTIVE NANOSTRUCTURES 765
ULTRAFAST PHASE TRANSITIONS IN SOLIDS 765
STIMULATED EMISSION OF Nd0 5La0 SAIJCBOJ^ RANDOM LASER AND THE THRESHOLD CONDITIONS FOR LARGE AND SMALL PUMPING REGIMES 766
SPECTROSCOPY AND OPTICAL MICROSCOPY WITH NANO-LOCAL LIGHT SOURCES 767
THE SIZE-EFFECT AND PHASE TRANSITIONS-EFFECT ON LUMINESCENCE PROPERTIES OF BaTiO3:Eu3+NANOCRYSTALLITES PREPARED BY THE SOLGEL METHOD 767
ENERGY TRANSFER IN Nd3+ and Yb3+ DODOPED NANOMETRIC YAG CERAMICS 768
ENVIRONMENT AND SHAPE EFFECTS ON DYNAMICS OF CdSe NANOCRYSTALS: COMPARING QUANTUM DOTS AND RODS 768
GAMMA AND PROTON IRRADIATION EFFECTS ON KU1 QUARTZ GLASS 769
FEATURES OF FEMTOSECOND LASER ABLATION OF SOLID TARGETS 769
STUDY OF THE SURFACE OF SrTiO3 SINGLE CRYSTALS BY OPTICAL SECOND HARMONIC GENERATION 770
DLS MEASUREMENT OF NANOMETRIC CARBON CLUSTERS PRODUCED IN LAMINAR PREMIXED FLAMES 771
INDEX 773

1. INVESTIGATING PHYSICAL SYSTEMS WITH OPTICAL SPECTROSCOPY (p. 1)

B. DI BARTOLO
Department of Physics, Boston College
Chestnut Hill, MA 02467, USA
Abstract
The article is based on the lectures that I delivered at the beginning of the course "Frontiers of Optical Spectroscopy," a NATO Advanced Study Institute that took place at the Ettore Majorana Center in Erice, Italy, May 16 - June 1, 2003. The purpose of this contribution is to present some background material useful to deal with the application of optical spectroscopy to the study of physical systems. In the introductory lecture we differentiate between two cases of "extreme physical conditions":

i) extreme conditions that predate experimentation, having been produced artificially and objectively different from more common ones, and

ii) extreme conditions created by an experimenter who employs some technical procedure to vary or modify the status of some systems and bring them into conditions different from their natural ones.

In the second lecture we treat the interaction of radiation with atoms and molecules. We introduce the concept of transition rate. In addition, we deal with the optical Bloch equations, the Rabi oscillations, and the mechanisms responsible for the broadening of spectral lines.

1. Introduction
At the beginning of the NATO Advanced Study Institute on "Frontiers of Optical Spectroscopy - Investigating Extreme Physical Conditions with Advanced Optical Techniques," I thought it was appropriate to present to the participants some considerations regarding the nature and purpose of such conditions. I want to report in this introduction these considerations, incorporating in them some of the input from the audience.

As suggested by a participant, "extreme" is a relative term, and conditions that may seem extreme today may, at a later time, be considered normal. We shall then at this point appraise the situation in terms of today's experimental reality. Extreme physical conditions are sought or prepared for in several human endeavors. An engineer, when building a bridge, will make himself sure that it will withstand much stronger pressure that it is ever likely to experience.

For a scientist extreme physical conditions of a system under study provide an appropriate situation in which the relevance of a certain parameter is enhanced and therefore made more amenable to be studied and understood. Examples that come to mind are the medical observation of patients walking on a treadmill and the study of orthophrenic children.

Claude Bernard (1813-1878) in his treatise on experimental medicine [1] makes a distinction between the observer and the experimenter:

"We give the name of the observer to somebody who applies the procedures of investigation, that may be simple or complex, to the study of phenomena that he does not influence and who collects the data as nature provides them.

We give the name of the experimenter to somebody who employs the procedures of investigation in order to vary or modify in some way the natural phenomena and make them appear in circumstances or conditions that are different from those in which nature will ever present them." In this scheme of things astronomy is a science of observation, because an astronomer cannot act on the celestial bodies and chemistry is a science of experimentation, because chemists act on nature and modify it.