1. "NANO-ACOUSTICS AND TERAHERTZ ACOUSTICS"
UNIVERSITE
Pierre & Marie CURIE
La science à PARIS
"NANO-ACOUSTICS AND TERAHERTZ ACOUSTICS"
Bernard Perrin
International Workshop on
« Nanoscale Energy Conversion and Information Processing Devices »
- September 24-26, 2006, Nice - France - 

2. Sound wave velocity in solids
5 – 10 nm/ps
Probing vibrations
at the nanoscale LA TA
Fréquency n (THz) 10
1,0
10-3
10-4
10-2
10-1
10-5
piezo
Brillouin
Picosecond
acoustics
IXS
Wavevector q/p (u.a.)
nano-systems
neutron
Phonons :
nm scale
THz range
Ballistic phonon heat transport
Picosecond acoustics
(H. Maris, 1985)
What can be done with an optical pump probe technique to increase the frequency range of laser ultrasonics?
Phonon engineering
Phonon nanocavities

3. Nanometric sonar in thin films
probe
pump
Lsubstrate > a few hundreds mm
Lfilm > a few tens nm
substrate
reflectometry
interferometry
Nanometric sonar
in thin films

4. Distorsion over large distance propagation ( > 0.1 mm)
Lattice dispersion
Lattice anharmonocity

5. Dispersion and nonlinearity : Solitons
(MgO)
Stable solution
(soliton)
150 fs
(1.4nm)

6. Multi-soliton formation
Rectangular initial strain
Area conservation

7. Acoustic Nonlinearity - Acoustic rectification
- Harmonic distorsion
- sound velocity = f()
- Acoustic rectification
GaAs
pump
probe
Al-30 nm
356 m
[100]

8. Expérience de réflectométrie en fonction de la puissance d'excitation

9. Expérience de réflectométrie en fonction de la puissance d'excitation

10. Expérience de réflectométrie en fonction de la puissance d'excitation

11. Expérience de réflectométrie en fonction de la puissance d'excitation

12. Expérience de réflectométrie en fonction de la puissance d'excitation

13. Expérience de réflectométrie en fonction de la puissance d'excitation

14. Expérience de réflectométrie en fonction de la puissance d'excitation

15. Ballistic propagation of heat pulsesQ
Black body radiation
Spectrum
up to a few THz
Z-cut in Sapphire - T = 3.8 K
time
longitudinal phonons
tranverse phonons

16. GaAs/AlAs

18. Can we do the same with a pump probe technique?
First longitudinal coherent
acoustic echo (one way trip)
T = 15 K
GaAs
pump
probe
Al-30 nm
356 m
[100]
reflectometry
One way +
6 round trips
2 round trips
interferometry

19. Temperature dependence
Q = 0.12 nJ

20. XY scan in the detection surface 12 K - Q=0.6 nJ m) m Position (
pump Al
30 nm
probe at
different
locations
XY scan in the
detection surface 30 60 1 3 13
200
400
600
800
1000
1200
1400
Position ( m m)
Delay (ps)
12 K - Q=0.6 nJ
Heat pulse :
moving acoustic
source
vph.
vst.
vstvph : building up of
a large matter displacement

21. Phonon engineering and acoustic nanocavity

24. Acoustic mirror
Acoustic nanocavity

25. Nanocavity used as a phonons generator
GaAs
356 µm
pump
probe
Nanocavity used as a phonons generator
cavity

26. Selective excitation of the cavity mode

28. Nanocavity or mirror used as a phonon detector
GaAs
probe
pump
Nanocavity or mirror used as a phonon detector
356 µm
Acoustic
mirror

29. Laurent Belliard – INSP Alex Fainstein – Institut Balseiro (Bariloche)
Phonon engineering in the subterahertz range is possible
Semiconductor superlattices work as excellent acoustic Bragg mirrors
Acoustic nanocavity has been evidenced
A first step towards a SASER
Laurent Belliard – INSP
Alex Fainstein – Institut Balseiro (Bariloche)
Agnès Huynh - INSP
Bernard Jusserand - INSP
Daniel Kimura- Lanzillotti
(INSP/Institut Balseiro - Bariloche)
Aristide Lemaitre (LPN – Marcoussis)
Emmannuel Péronne - INSP
Shuo Zhang - INSP

30. 12th international conference
Phonons in nanostructures and low-dimensional structures
Ultrafast acoustics
Coherent phonons
Micro and nano acoustics
MEMS and NEMS (micro and nano electromechanical systems)
Phonons in devices for electronics, optoelectronics and spintronics
Electron-phonon interaction
Micro and nanoscale phonon heat transfer
Nanoscale energy conversion and thermo-electricity
Phonon transport
Solitons and nonlinear phenomena
Acoustic waves in anisotropic media and phonon imaging
Phonons in superconductors and magnetic materials
Phononic crystals
Surface and Interface phonons
Quantum fluids
Lattice dynamics
Phonons in glasses and disordered systems
Phase transitions
Light, neutron and X-ray inelastic scattering
New techniques
Particle detectors
July 15–20, 2007
12th international conference
on phonon scattering
in condensed matter