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
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
Diagnostic: Green laser
scattering from suspended particle
P. Rohwetter et al., Nature Photonics 4, 451 (2010)
8/05/2013 LNF-INFN
Cloud chamber sub-saturated
RH=(70-90)%
T=20C
Y. Petit, Appl. Phys. Letters, 98, 041105 (2011)
S. Henin et al, Nature Communication, 2,456, 2011
Massimo Petrarca
100TW laser induced particle generation in controlled atmosphere
(Dresden 2011)
Cloud chamber
L=7 propagation in air
Ti:Sa laser
chain
RH=(75-95)%
T=(8-12)C
l0=800nm
E=3J
FWHM=30fs
P=100TW
Beam size ~ 100cm2
Gas analyzer Grimm
Aerosol particle detection: Grimm
32 size classes: 250-30mm
Nanocheck =(25-300)nm
condensation
chambre
laser in
Grimm
laser out
gas
probe
8/05/2013 LNF-INFN
2.3J,30fs
Grimm
Massimo Petrarca
Result Dresden 2011
Threshold Contribution grows Contribution of
photon bath
with
number of filaments
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, 141103 (2011)
8/05/2013 LNF-INFN
Massimo Petrarca
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
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
8/05/2013 LNF-INFN
Massimo Petrarca
FLAME bunker , Floor: underground
8/05/2013 LNF-INFN
Massimo Petrarca
8/05/2013 LNF-INFN
Massimo Petrarca
Detection system
Photomultiplierts (PMT)
Optical
beam line
8/05/2013 LNF-INFN
Lidar signal input
Massimo Petrarca
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
LIDAR signals
[V]
LIDAR signal-Green beam
LIDAR signal-Green beam
clouds
clouds
LIDAR signal -UV beam
LIDAR signal -UV beam
8/05/2013 LNF-INFN
Massimo Petrarca
[ms]
LIDAR signals
[V]
LIDAR signal-Green beam
clouds
clouds
LIDAR signal -UV beam
8/05/2013 LNF-INFN
Massimo Petrarca
[ms]
Results and Outlook
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 ; 400nm + 800nm as PUMPS
8/05/2013 LNF-INFN
Massimo Petrarca
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