An Absolute Method of Measuring Energy Outputs from CO2 Lasers

Abstract

Articles you may be interested inAbsolute calibration method for laser megajoule neutron yield measurement by activation diagnostics Rev. Sci. Instrum. 82, 073501 (2011); 10.1063/1.3605485Quartz crystal microbalance measurements of absolute laser photodeposition rates: Application to 257nm deposition from W(CO)6In the energy meter described here the CO 2 laser radiation is almost completely absorbed by an Al 2 0 3 surface on an aluminum plate. The high absorption of the surface (z9S%) eliminates the need for calibration and the laser energy is computed by measuring the temperature rise of a plate with known thermal capacity. Experimentally we find that the calorimeter noise level corresponds to an energy density of about 2 mJ/cm 2 • Calculations indicate that the instrument is capable of measuring the energy of a single pulse that is 1 nsec wide, provided the pulse contains an average energy density of 10 mJ/cm 2 • We have estimated the radiation and convection losses and found them to be negligible. The calorimeter is good for radiation between 8.5 and 11 !J.; however, with modifications the bandwidth could easily be increased.

Pulsed CO<inf>2</inf>lasers for the surface heating and melting of metals

“…Pulse energy was measured with commercial calorimeters or with a flat-plate calorimeter of anodized aluminum [2] . The pulse shape is observed with photon-drag or barium-titanate detectors.…”

“…Metal surface melting is easily achieved, even with modest pulsed lasers; no obstacle to the melting of any metal, including refractory types, is apparent. [see ( 2 ) ] . Some recent data [34] reveal in fact a dependence of form h-' , showing that our analysis is deficient.…”