Automated power-in-the-bucket measurement apparatus for large aperture laser systems

A beam quality measurement system for measuring the beam quality of a high power laser beam from a laser system in a laboratory environment, said system comprising:

• a beam compressor assembly for compressing the diameter of the high power laser beam, said beam compressor assembly including an outer enclosure and an input window through which the high power laser beam enters the enclosure, said beam compressor assembly further including a beam compressing telescope that receives the high power laser beam from the input window and reduces the diameter of the high power beam, said beam compressor assembly further including a first high power beam splitter that splits the reduced diameter beam into a reduced diameter high power beam and a reduced diameter low power beam;
• a diagnostic bench assembly that receives the reduced diameter low power beam from the beam compressor assembly, said diagnostic bench assembly including a first lens that focuses the reduced diameter low power beam and a plurality of optical components including a plurality of beam splitters and a plurality of folding optics, said diagnostic bench assembly further including a pinhole array assembly having a pinhole array positioned at a focal plane of the first lens and including a plurality of different sized pinholes and a translation stage for moving the pinhole array in three degrees of freedom so as to selectively position the pinholes at a focal point of the first lens in the focal plane, said diagnostic bench assembly further including a first power meter that receives the focused beam after it has passed through a pinhole in the pinhole array and measures the power of the focused beam, and a position sensing detector that is positioned at the focal plane of the first lens and measures the position of the focused beam so as to identify jitter in the low power beam, and a second lens positioned between the pinhole array and the first power meter that collimates the focused beam onto the first power meter, wherein the first power meter generates a signal that causes the translational stage to move the pinhole array so that another pinhole in the array is positioned at the focal point of the first lens when the first power meter identifies a maximum power received from one pinhole;
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• a second high power beam splitter positioned outside of the enclosure and receiving the high power beam from the first beam splitter, said second beam splitter splitting the beam into a high power beam portion that is sent to a heat dump and low power beam portion that is received by a second power meter, said second power meter measuring the power of the beam for calibrating the low power beam.