Femtosecond Laser Filamentation

by Chin, See Leang

• ISBN13: 9781441906878
• ISBN10: 1441906878
• Format: Hardcover
• Copyright: 2009-12-30
• Publisher: Springer Verlag

Summary

When a powerful femtosecond laser pulse propagates in an optical medium, self-focusing occurs. This book reviews the current up-to-date understanding of the physics of propagation leading to the self-transformation of the laser pulse into a white light laser pulse during self-focusing and filamentation. The physics of multiple filamentation and competition will be discussed. Its capability to melting glasses inside the filaments is observed which explains the physics of wave guide writing. Its potential applications in atmospheric sensing and material processing together with possible future challenges in the interaction of such self-transformed white light laser pulses with atoms and molecules will be treated. Nonlinear optics such as third harmonic generation in the filaments with self-phase locking will also be discussed.

Table of Contents

Introduction	p. 1
Mature Physics and New Development	p. 1
Phase Effect of a Laser Pulse Propagating in an Optical Medium	p. 3
Multiphoton and Tunnel Ionization	p. 4
Optical Breakdown	p. 6
Intense Femtosecond Laser Beam Attenuation	p. 8
Filamentation Physics	p. 11
Some Experimental Observations	p. 11
Experimental Definition of a Filament by Bum Paper	p. 15
Single Filamentation Physics	p. 16
Slice-by-Slice Self-Focusing	p. 16
Intensity Clamping	p. 21
Is There Optical Breakdown During Filamentation?	p. 23
Effect of External Focusing	p. 25
Background Energy Reservoir	p. 26
Self-Spatial Mode Filtering	p. 31
Self-Phase Modulation, Self-Steepening and White Light Laser (Supercontinuum)	p. 32
Conical Emission	p. 36
Ring Structure at the Pump Wavelength	p. 38
Self-Pulse Compression	p. 38
X-wave	p. 40
Full Evolution of a Single Filament	p. 40
Maturity of a Filament	p. 46
Filamentation Without Ionization	p. 46
What Is a Filament?	p. 47
Theory of Single Filamentation	p. 49
Introduction	p. 49
Filamentation in Air	p. 49
Numerical Solution of Filamentation in Air	p. 51
Filamentation in Condensed Matter	p. 55
x-Wave and Conical Emission	p. 55
Multiple Filamentation	p. 61
Introduction	p. 61
Multiple Filamentation: Experimental Observation	p. 61
Interference and Competition of Multiple Filaments	p. 64
Theory of Multiple Filamentation	p. 67
The Challenge of Long Distance Filamentation	p. 68
Long Distance Multiple Filamentation Control	p. 68
Filamentation Nonlinear Optics: General	p. 71
Self-Actions	p. 71
Self-Remote Projection in Air	p. 72
Self-Pulse Compression	p. 74
Exploitations of the Self-Actions	p. 74
Filamentation Nonlinear Optics: Third Harmonic Generation and Four-Wave-Mixing Inside a Filament	p. 77
Introduction	p. 77
Third Harmonic Generation Inside a Filament in Air (Theoretical Analysis)	p. 77
Experiment on THG in Air	p. 83
Conical Emission and Superbroadening of the Third Harmonic in Air	p. 85
Efficient Tunable Few Cycle Visible Pulse Generation Through Four-Wave-Mixing Inside the Filament Core	p. 85
Self-Group-Phase Locking During Four-Wave-Mixing Inside a Filament	p. 88
Derivation of Equation (6.1)	p. 89
Remote Sensing Using Filamentation	p. 93
Introduction	p. 93
Remote Control of Filamentation	p. 94
Physical Considerations	p. 96
Detection of Chemical and Biological Agents in Air	p. 97
Molecules in the Gas/Vapor Phase	p. 97
Biological Targets	p. 99
Metallic Targets	p. 100
Water Aerosols Containing Metallic Salts	p. 100
Conclusion and Looking Ahead	p. 101
Challenges Ahead	p. 103
Multiple Filamentation	p. 104
Why Does a Large Diameter Beam Diverge Slowly Over Long Distances When There Is Multiple Filamentation?	p. 104
Filament Collaboration	p. 104
Optimum Wavelength to Produce the Broadest and Strongest White Light	p. 105
Filament Control Using a Deformable Mirror	p. 105
Time-Resolved Excitation of Superexcited States of Molecules	p. 106
Ultrafast Birefringence	p. 109
Filament-Induced Birefringence	p. 110
Excitation of Molecular Rotational Wave Packets in Air and Polarization Separation	p. 114
Just the Beginning of Filament-Induced Birefringence	p. 118
References	p. 119
Index	p. 125
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