TY - JOUR
T1 - Micron-sized dropiets irradiated with a puised CO2 laser
T2 - Measurement of expiosion and breakdown threshoids
AU - Pinnick, Ronald G.
AU - Biswas, Abhijit
AU - Armstrong, Robert L.
AU - Gerard Jennings, S.
AU - David Pendleton, J.
AU - Fernández, Gilbert
PY - 1990/3
Y1 - 1990/3
N2 - Meeisurements of minimum CO2 laser fluence required to explode or disintegrate 10-60 μm radius droplets of water, ethanol, diesel (hexadecane), CCI4, bromoform, and ethyl bromide are reported. Threshold fluences range from 0.4 J cm-2 for 10-μm radius ethanol drops to 20 J cm-2 for 30-μm bromoform drops. Threshold fluences for water droplets are ˜3 J cm-2 independent of drop size. Comparison of the measurements to calculations of laser fluence required for considered absorbing droplets to reach superheat temperature is in good agreement for cases where liquid material properties are known, suggesting that superheating of droplets is the dominant mechanism causing explosion/disintegration. Measured droplet-induced laser breakdown thresholds are considerably higher than explosion thresholds and have less dependence on droplet size and composition. The highest breakdown threshold values are for water drops, which range from 150 to 280 J cm-2 (0.9-1.7 × 109 W cm-2) compared with 670 J cm-2 (4.0 × 109 W cm-2) for clesm air breakdown for the laser pulse length and spot size.
AB - Meeisurements of minimum CO2 laser fluence required to explode or disintegrate 10-60 μm radius droplets of water, ethanol, diesel (hexadecane), CCI4, bromoform, and ethyl bromide are reported. Threshold fluences range from 0.4 J cm-2 for 10-μm radius ethanol drops to 20 J cm-2 for 30-μm bromoform drops. Threshold fluences for water droplets are ˜3 J cm-2 independent of drop size. Comparison of the measurements to calculations of laser fluence required for considered absorbing droplets to reach superheat temperature is in good agreement for cases where liquid material properties are known, suggesting that superheating of droplets is the dominant mechanism causing explosion/disintegration. Measured droplet-induced laser breakdown thresholds are considerably higher than explosion thresholds and have less dependence on droplet size and composition. The highest breakdown threshold values are for water drops, which range from 150 to 280 J cm-2 (0.9-1.7 × 109 W cm-2) compared with 670 J cm-2 (4.0 × 109 W cm-2) for clesm air breakdown for the laser pulse length and spot size.
UR - https://www.scopus.com/pages/publications/84975624050
U2 - 10.1364/AO.29.000918
DO - 10.1364/AO.29.000918
M3 - Article
AN - SCOPUS:84975624050
SN - 1559-128X
VL - 29
SP - 918
EP - 925
JO - Applied Optics
JF - Applied Optics
IS - 7
ER -