1. LIDAR experiment In-situ laser-induced condensation in free atmosphere
M. Petrarca
Collaboration
LNF/INFN-University of Geneva GAP
8/05/2013 LNF-INFN
Massimo Petrarca

2. Overview
It has been shown that is possible to trigger the formation of water droplets by intense laser beam in the filamentation regime while propagating in a controlled atmosphere with saturated and unsaturated relative humidity
Background: No IR laser, no filament
Cloud chamber sub-saturated
RH=(70-90)%
T=20C
Diagnostic: Green laser
scattering from suspended particle
P. Rohwetter et al., Nature Photonics 4, 451 (2010)
Y. Petit, Appl. Phys. Letters, 98, (2011)
S. Henin et al, Nature Communication, 2,456, 2011
8/05/2013 LNF-INFN
Massimo Petrarca

3. 100TW laser induced particle generation in controlled atmosphere (Dresden 2011)
2.3J,30fs
RH=(75-95)%
T=(8-12)C
Cloud chamber
L=7 propagation in air
Ti:Sa laser chain
l0=800nm
E=3J
FWHM=30fs
P=100TW
Beam size ~ 100cm2
Gas analyzer
Grimm
Aerosol particle detection: Grimm
32 size classes: mm
Nanocheck =(25-300)nm
laser in
laser out
gas
probe
condensation chambre
Grimm
8/05/2013 LNF-INFN
Massimo Petrarca

4. Result Dresden 2011 Threshold Contribution grows with
number of filaments
Contribution of
photon bath
A relevant increase of the nano-particle signal growing faster than linearly with power and number of filaments, is evidenced. This contribution comes from the “bath”
M. Petrarca et al., Appl. Phys. Lett. 99, (2011)
8/05/2013 LNF-INFN
Massimo Petrarca

5. LIDAR experiment proposal to study the scaling up in power and energy of the effect in real uncontrolled atmosphere
SPARC_LAB/LNF-INFN
8/05/2013 LNF-INFN
Massimo Petrarca

6. Experiment set-up and strategy
1) Pump: Flame laser beam into atmosphere:
2) Probe: UV +Green beams in LIDAR configuration
 Ozone + Aerosols detection
3) White-light FLAME induced Lidar signal
4) Quantify total PUMP laser effect
FLAME bunker , Floor: underground
8/05/2013 LNF-INFN
Massimo Petrarca

7. 8/05/2013 LNF-INFN
Massimo Petrarca

8. 8/05/2013 LNF-INFN
Massimo Petrarca

9. Detection system Photomultiplierts (PMT) Optical beam line
Lidar signal input
8/05/2013 LNF-INFN
Massimo Petrarca

10. PXI: acquisition hardware 1.2MB each file at 10Hz
6 curves saved in each file
FLAME control room
8/05/2013 LNF-INFN
Massimo Petrarca

11. LIDAR signals [V] [ms] LIDAR signal-Green beam LIDAR signal-Green beam
clouds
clouds
LIDAR signal -UV beam
LIDAR signal -UV beam
[ms]
8/05/2013 LNF-INFN
Massimo Petrarca

12. LIDAR signals [V] [ms] LIDAR signal-Green beam clouds clouds
LIDAR signal -UV beam
[ms]
8/05/2013 LNF-INFN
Massimo Petrarca

13. Results and Outlook Future
Data analysis still under in progress….strong back ground signal (aerosols) to be disregarded opportunely, signal is present
Future
Collinear configuration of the PUMP+PROBES with beam collimation
Sweeping time delay PUMP vs PROBES
Particle generation optimization by adaptive optics
Optimization (adaptive optics) of white light and its characterization
FLAME converted SHG (800400)nm:
400nm beam as PUMP ; nm + 800nm as PUMPS
8/05/2013 LNF-INFN
Massimo Petrarca

14. Participants
University of Geneva: M. P., S. Henin, M. Gosal, N. Berti,
J. Chagas, J. Kasparian, Prof. J.P. Wolf
LNF-INFN: M. P., G. Gatti, M. Anania, G. Di Pirro, R. Sorchetti,
L. Cacciotti, M. Ferrario, A. Ghigo
8/05/2013 LNF-INFN
Massimo Petrarca