Christophe Huchon
Nanoscale Physics Research Laboratory
School of Physics and Astronomy
The University of Birmingham
United Kingdom
Attosecond meeting, 7 december 2005, Rutherford Appleton Laboratory
Time of flight measurement of femtosecond ablation of graphite
Motivation: mechanism(s) in femtosecond laser ablation ?
TOFProducts ONLY
from surface ?
TOF Products from
surface + fragmentation ?
Thermal (equilibrium)
or/and
coulomb explosion (non equilibrium)?
Nd:YLF1 kHz = 527 nm
Up to 25 mJ
RegenerativeAmplifier
1 kHz100 fs
Up to 2 mJ
Ti:Sapphire,82 MHz, 800 nm,
100 fs, 600 mW
Ar+ laserAll lines
6 W
Argon gas flow
Transfer arm
PMTDifferentialpumpingchamber
STMchamber
Ablationchamber
Time-of-flightspectrometer
HHGchamber
LAYOUT PUMP-PROBE
Principle of TOF spectrometer
m
mU0
eV Ions desorbed from surface: if D >> s
s D
Source/extraction Drift region Detector
E2 = 0 E1 = V/sV
QuickTime™ and aTIFF (LZW) decompressor
are needed to see this picture.QuickTime™ and a
TIFF (LZW) decompressorare needed to see this picture.
Model used for ablation process
QuickTime™ and aTIFF (LZW) decompressor
are needed to see this picture.
C1
C7
C3
C2
Ratio ≈ 11
pulse= 100 fs
Epulse= 200 J
Usample= 500 V
QuickTime™ and aTIFF (LZW) decompressor
are needed to see this picture.
C2
C3
C4
pulse= 100 fs
Epulse= 10.5 J
Usample= 405 V
KE distribution spread as a function of the voltage
QuickTime™ and aTIFF (LZW) decompressor
are needed to see this picture.
pulse= 100 fs
Epulse= 10.5 J
Summary
• fragmentation process involved in the ablation of the graphite with femtosecond laser pulse.
• need to find what is the rate thermal vaporization / Coulomb explosion VUV probe
• VUV, XUV will allow time-resolved photoelectron emission
Acknowlegdement
• Andrey Kaplan
• Miklos Lenner
• Quanmin Guo
• Richard Palmer
