high-harmonic generation from noble gases exposed to intense laser fields gavin waters supervisor:...
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Diagram: P. Agostini, L. F. DiMauro; 'ThDiagram: P. Agostini, L. F. DiMauro; 'The Physics of Attosecond Light Pulses' Re Physics of Attosecond Light Pulses' Rep. Prog. Phys. 67 (2004) 813-855ep. Prog. Phys. 67 (2004) 813-855
High-harmonic generation High-harmonic generation from noble gases exposed from noble gases exposed
to intense laser fieldsto intense laser fields
Gavin WatersGavin Waters
Supervisor: Dr. L. J. FrasinskiSupervisor: Dr. L. J. Frasinski
Diagram: Y. Mairesse et al; 'AttoseconDiagram: Y. Mairesse et al; 'Attosecond Synchronization of High-Harmonic Sd Synchronization of High-Harmonic Soft X-rays' Science, Vol 302, 28 Noveoft X-rays' Science, Vol 302, 28 November 2003, 1540-1543 mber 2003, 1540-1543
Schematic Diagram of Equipment Schematic Diagram of Equipment
Diagram: P. Agostini, L. F. DiMauro; 'ThDiagram: P. Agostini, L. F. DiMauro; 'The Physics of Attosecond Light Pulses' Re Physics of Attosecond Light Pulses' Rep. Prog. Phys. 67 (2004) 813-855ep. Prog. Phys. 67 (2004) 813-855
Three-step Model of HHGThree-step Model of HHGStep 1: Tunnel ionization
Step 2: Quasi-classical electron acceleration in strong laser field
Step 3: Electron-nucleus recombination, emission of High Harmonic photon
Due to this process occurring every half of the optical cycle of the driving beam, only photons of frequency that are odd harmonics of the driving beam are produced
Diagram: J. Itatani et al; ' TomographicDiagram: J. Itatani et al; ' Tomographic Imaging of Molecular Orbitals' Nature, Imaging of Molecular Orbitals' Nature, Vol 432, 16 December 2004, 867-871 Vol 432, 16 December 2004, 867-871
Electron Wave-packet Model of Electron Wave-packet Model of HHGHHG
Electron now represented by its wave-function, ψ
Part of the wave-function, ψg, remains in the ground state
Remaining part of wave-function, ψc, interferes with ψg on re-collision
This interference effect leads to an electron charge oscillation, and the emission of High Harmonic radiation
Diagram: J. Tisch, Imperial CollegeDiagram: J. Tisch, Imperial College
Technical Drawing of Technical Drawing of ApparatusApparatus
Side view of the HHG equipment. Equipment designed by J. Tisch (Imperial College). The two main components shown are HHG chamber (right) and mirror chamber (left).
Diagram: J. Tisch, Imperial CollegeDiagram: J. Tisch, Imperial College
Technical Drawing of Technical Drawing of ApparatusApparatus
Top down view of the HHG equipment.
Red line represents driving laser beam (pulse duration about 30fs).
Green line represents HHG laser beam (pulse duration less than 1fs).
Diagram: P. Agostini, L. F. DiMauro; 'ThDiagram: P. Agostini, L. F. DiMauro; 'The Physics of Attosecond Light Pulses' Re Physics of Attosecond Light Pulses' Rep. Prog. Phys. 67 (2004) 813-855ep. Prog. Phys. 67 (2004) 813-855
HHG equipment used in Saclay HHG equipment used in Saclay experimentexperiment
Diagram: P. Agostini, L. F. DiMauro; 'ThDiagram: P. Agostini, L. F. DiMauro; 'The Physics of Attosecond Light Pulses' Re Physics of Attosecond Light Pulses' Rep. Prog. Phys. 67 (2004) 813-855ep. Prog. Phys. 67 (2004) 813-855
Mirror Chamber used in Saclay Mirror Chamber used in Saclay ExperimentExperiment