Attosecond pulses produced by using HHG in gases, it is possible to make a few simple statements: attosecond pulses are unique tools for the investigation of ultrafast electronic processes in atoms, molecules, nano structures and solids. Impressive progress has been demonstrated from the technological point of view, with the possibility to routinely generate attosecond pulses in perfectly reproducible ways.

1. GENERATION AND
APPLICATION OF ATTOSECOND
LASER PULSE
CHIKKPETI
Sachidanand

2. INTRODUCTION
• The advent of subfemtosecond or attosecond (as) light pulses
will open new fields of time-resolved studies with
unprecedented resolution. Just as subpicosecond or
femtosecond (fs) pulses have allowed the resolution of
molecular movements, attosecond pulses may enable us to
resolve electronic dynamics
• To create a light pulse with this duration, the central frequency
has to be in the XUV range and cover several tens of eVs.
Moreover, the frequency components have to be synchronized.
The so called High Harmonic Generation (HHG) in gases well
suits this task.

3. HIGH HARMONIC GENERATION
• There are mainly three steps to generate the HHG
1.TUNNEL IONIZATION:-
2.MOTION AFTER LIBERATION:-
3.RECOMBINATION
IONIZATION
When induced by a strong (near-)infrared
laser field, ionization can be approximated by
tunnelling
A typical electron will gain a kinetic energy
of ∼50–1,000 eV from the field during its first
femtosecond of freedom, representing tens to
hundreds of photons
. On re-encountering the core, the electron
scatters from its parent ion , On recollision
the free, Ψc, and the bound, Ψg, components
of the (coherent) total wavefunction interfere,
producing an oscillating dipole that emits
light

4. GENERATION ATTOSECOND PULSE USING HHG WITH
ELECTRON INTERFEROMETER
F=ma
In addition to producing attosecond electron and photon pulses, the recollision simultaneously encodes all information on
the electron interference. Once the amplitude and phase of the electron interference is encoded in light, powerful optical
methods become available to 'electron interferometry'.
Overlap
Beam
splitter-
tunneling

5. HIGH HARMONICS AND ATTOSECOND TRAIN
PULSES
Attosecond pulses
repeated each half
period create a series of
femtosecond duration
harmonics. They can
extend to more than
1kev if needed
ARGON ATOM AT
800nm

6. PRODUCING HIGH HARMONIC ATTOSECOND
PULSE
Amplitude and
phase recollision
of electron
transferred to the
light in (dt)
direction.

7. GENERATE ISOLATED ATTOSECOND PULSE
Comparison of the experimental HHG autocorrelation data
(normalized) from Ar driven by ∼10 cycle laser pulses at
wavelengths of (A) 0.8 μm, (B) 1.3μm, and (C) 2 μm for high and
low laser intensity conditions (red and blue lines
Schematic of the setup for attosecond high-
resolution Fourier transform spectroscopy.
In our experiment, laser pulses at wavelengths of
0.8, 1.3, and 2.0 μm are generated using a 1-kHz
Ti:sapphire laser pumping a three-stage optical
parametric amplifier (OPA). The pulse durations at all
three wavelengths were adjusted to be ∼10 cycles in
duration (24 fs at 0.8 μm – 9.5 cycles, 35 fs at 1.3 μm –
8 cycles and 90 fs at 2.0 μm – 13.5 cycles)

8. GRATING METHODS FOR ISOLATED
ATTOSECOND PULSE
They are mainly categorised by three parts as given by the following
1. INTENSITY GRATING
Uses high intensed single cycle
pulse
2. POLARIZATION GRATING
They are mainly of three types
Collinear polarization
grating
Double Optical Gating
Generalized Double
Optical Gating
Scheme of collinear polarization
gating.

9. 3. TWO COLOUR GRATING
Augment using these second
harmonic
Two colours polarisation
grating

10. • There are few important applications of attosecond pulses to atomic,
molecular and solid-state physics.
• (i) Measurement of temporal delays in photoemission from atoms
and solids;
• (ii) Investigation of electron correlation processes in multi-electron
systems; (iii) a brief report on the main applications of attosecond
pulses to the measurement of ultrafast molecular dynamics;
• (iv) First experimental evidence of charge migration in biologically
relevant molecules;
• (v) Applications of attosecond pulses to solid-state physics.
APPLICATIONS
:-

11. CONCLUSION
• After the first demonstration of the generation of attosecond
pulses, produced by using HHG in gases, it is possible to make
a few simple statements: attosecond pulses are unique tools for
the investigation of ultrafast electronic processes in atoms,
molecules, nanostructures and solids. Impressive progress has
been demonstrated from the technological point of view, with
the possibility to routinely generate attosecond pulses in
perfectly reproducible ways. Several new experimental
approaches have been proposed and implemented, which allow
real-time observation and control of ultrafast electronic events
at the heart of several important processes.

12. REFERENCES
• Advances in attosecond science:-
http://iopscience.iop.org/article/10.1088/0953-4075/49/6/062001
• Generation and Measurement of Attosecond Pulses - Paul
Corkumhttps://www.youtube.com/watch?v=XHjLSIVeaZg&t=1504s
• http://www.pnas.org/content/pnas/111/23/E2361.full.pdf
• https://tel.archives-ouvertes.fr/tel-
00722473/file/VA2_ZSOLT_DIVEKI_13122011.pdf
• https://www.researchgate.net/post/how_we_can_generate_attosecon
d_laser_pulses
• https://www.creol.ucf.edu/Research/Publications/8620.pdf