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Prof Ian Williams Dr B. Srigengan Mr M. Suresh Mr Jarlath McKenna. Prof Roy Newell Dr Will Bryan Mrs Sarah Watson Miss Elizabeth English. Dr John Collier Dr Andrew Langley Dr Edwin Divall Dr Chris Hooker. Xe atoms and ions in circularly and linearly polarized fields.
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Prof Ian Williams Dr B. Srigengan Mr M. Suresh Mr Jarlath McKenna Prof Roy Newell Dr Will Bryan Mrs Sarah Watson Miss Elizabeth English Dr John Collier Dr Andrew Langley Dr Edwin Divall Dr Chris Hooker Xe atoms and ions in circularly and linearly polarized fields HPLUM 17 December 2003
Femtosecond Lasers • Ti: Sapphire at 790 nm (1.6 eV) • Chirped Pulse Amplification • Terawatt (1012 W) Lasers ASTRA ~20 mJ in ~50 fs in TA1 • High field physics ~ 1017 Wcm-2 1 au = 3 x 1016 Wcm-2 • Repetition rate 10 Hz
ION BEAM TOFMS Bottom plate Gas-line Top plate Drift tube Detector housing Apparatus Overview
e- e- Ionization Potential well Keldysh Parameter, Electric field Atomic Potential well V0(x) x0 Ponderomotive Potential, UP Potential range (x) I in Wcm-2 & in m
Rescattering Model Linearly Polarized Field Xe + 2 CORE
Xe+ CORE Circularly Polarized Field
Z Xe2+ Xe3+ Xe4+ Volume Effects & ISZ-Scanning
132Xe2+ 131Xe2+ 129Xe2+ Xe8+ Xe7+ Xe6+ Xe4+ Xe3+ Xe5+ Xe2+ Xe+ Z-scan results from Xe neutral target Signal (arb.) Xe+ Time of Flight (sec) Xe2+ Xe3+ Xe4+ Xe5+ Xe6+ Xe7+ Xe8+ Z Position (arb.) Typical time-of-flight spectra (z=0mm)
Green-Linear-1.3Io Blue- Circular-IO Total Xe+ Xe2+ Xe3+ Xe4+ Xe5+ Xe7+ Xe8+ Xe6+
g= 0.5 where n* - effective principal quantum no. Z – charge state of residue ion e– E-field
Z-Scan Result of Ne2+ from Ne Black - Linear-1.3Io Blue- Circular Io
ratio ratio Comparison…. t Ion Yield Ne Ne Xe Ion Yield Xe Single and double ionization of Ne and Xe Ratio between double and single ionization of Ne and Xe Becker and Faisal J Phys B 32 (1999) L335
Metastable population Xe+ 1.2%
4S03/2 Xe3+ 32.14eV 1G04 16.43eV 3G04, 5 16.40eV 15.51eV 3F04 13.83eV 5D04 3P2, 1, 0 Xe2+ 0.00eV 21.22eV 2F7/2 4F9/2, 7/2 4D7/2 2P03/2, 1/2 Xe+ 0.00eV Electronic states of Xe+ 5s25p3 5s25p4 14.26eV 12.33eV 11.84eV 5s25p5
Metastable population Xe2+ 3.7%
Green-Linear-1.3Io Blue- Circular-IO Total Xe+ Xe2+ Xe3+ Xe4+ Xe5+ Xe7+ Xe8+ Xe6+
Metastable population Xe2+ 3.7%
Metastable population Xe+ 1.2%
conclusion Suppression of NS Ionization in Circularly Polarized Field Volume Enhancement Results by ISZ-Scanning Technique No Significant NS Ionization in Ne2+