Absolute reference calorimeter for measuring high power laser pulses

A calorimeter for making absolute energy measurements of high power laser pulses is described. The calorimeter, based on volume absorption in a solid, is calibrated electrically and requires no window or vacuum environment. An error analysis is included giving the systematic and random errors of the instrument for a laser measurement. Briefly, the following performance is typical of the 32-mm x 32-mm aperture calorimeter: range 0.4-15-J; random error plus or minus 0.2% (one standard deviation); systematic error plus or minus 2.3%; and an upper operational limit of 3 J per sq cm. Most of the volume absorber documentation is applicable for 1.06 micron; however, the calorimeter should be useful from the near IR through the visible. Absorbers for use with CO2 lasers in the 9-11 micron range are also discussed.