High power laser beam intensity mapping apparatus

Apparatus for determining the spatial energy density distribution of an energy beam, such as a laser beam, comprising:

• (a) first means for scanning said beam in a first direction and being constructed and arranged to pass only a slit-shaped segment of said beam;
• (b) said first means including first and second mirror members each having a knife edge, with the knife edges being adjacent one another to permit passage of only said slit-shaped segment;
• (c) each said mirror member having a highly reflective surface oriented so as to redirect said beam, or any portion thereof which impinges upon said surface, to a direction non-coincident with the beam impingement direction;
• (d) second means for scanning said passed slit-shaped segment in a second direction and being constructed and arranged to pass, at any instant of time, only a small elemental portion of said segment;
• (e) detector means including a detector operable to provide an output signal in response to impingement of said beam;
• (f) means for directing said small elemental portion of said segment to impinge upon said detector;
• and
• (g) circuit means responsive to said output of said detector, generated during said scans, to provide an indication of said spatial energy density distribution of said beam.