LIDAR experiment Insitu laserinduced condensation in free atmosphere

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=20 C Y. Petit, Appl. Phys. Letters, 98, 041105 (2011) S. Henin et al, Nature Communication, 2, 456, 2011 Massimo Petrarca

100 TW laser induced particle generation in controlled atmosphere (Dresden 2011) Cloud chamber Ti: Sa laser chain L=7 propagation in air RH=(75 -95)% T=(8 -12)C l 0=800 nm E=3 J FWHM=30 fs P=100 TW Beam size ~ 100 cm 2 Gas analyzer Grimm Aerosol particle detection: Grimm 32 size classes: 250 -30 mm Nanocheck =(25 -300)nm condensation chambre laser in Grimm laser out gas probe 8/05/2013 LNF-INFN 2. 3 J, 30 fs 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. 2 MB each file at 10 Hz 6 curves saved in each file FLAME control room 8/05/2013 LNF-INFN Massimo Petrarca

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

LIDAR signals [V] LIDAR signal-Green beam 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: 400 nm beam as PUMP ; 400 nm + 800 nm 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