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Title: Laser plasma formation assisted by ultraviolet pre-ionization

We present experimental and modeling studies of air pre-ionization using ultraviolet (UV) laser pulses and its effect on laser breakdown of an overlapped near-infrared (NIR) pulse. Experimental studies are conducted with a 266 nm beam (fourth harmonic of Nd:YAG) for UV pre-ionization and an overlapped 1064 nm NIR beam (fundamental of Nd:YAG), both having pulse duration of ∼10 ns. Results show that the UV beam produces a pre-ionized volume which assists in breakdown of the NIR beam, leading to reduction in NIR breakdown threshold by factor of >2. Numerical modeling is performed to examine the ionization and breakdown of both beams. The modeled breakdown threshold of the NIR, including assist by pre-ionization, is in reasonable agreement with the experimental results.
Authors:
;  [1] ;  [2] ;  [3] ;  [4]
  1. Department of Mechanical Engineering, Colorado State University, Fort Collins, Colorado 80523 (United States)
  2. Sandia Laboratory, Albuquerque, New Mexico 87123 (United States)
  3. Cummins Inc., Columbus, Indiana 47201 (United States)
  4. Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, New Jersey 08544 (United States)
Publication Date:
OSTI Identifier:
22299723
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physics of Plasmas; Journal Volume: 21; Journal Issue: 10; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; AIR; BEAMS; BREAKDOWN; NEODYMIUM LASERS; PLASMA; PULSES; SIMULATION; ULTRAVIOLET RADIATION