Pulsed Operation: Upper limit of the operating space for pulsed laser measurements.
Slit Damage: Power density (watts/cm2 ) where one can begin to cut the slits. Refer to Photon's Aperture Damage due to High Incident Power document.
Left Boundary: Smallest beam size limited to 4-5 times the slit width. Some models have another limit due to electrical bandwidth.
Right Boundary: Instrument entrance aperture. The largest beam width (1/e2) will be the aperture divided by 1.2-1.4.