Spatial peak intensity (Isp) is the maximum in _______.

• A. Space
• B. Time
• C. Pulse duration
• D. Cross-sectional area of the beam

Answer: (A)

Spatial peak intensity is the highest value of intensity that occurs at any location across the beam’s cross-section—in space. Since intensity is power per unit area, the peak is found where the beam’s energy concentration is greatest somewhere within the beam cross-section, not over time or over the whole area. Temporal peak intensity would refer to the maximum at a single point over time during a pulse, not the maximum across space. Pulse duration is simply how long the emission lasts, and the cross-sectional area is the size of the beam, not where the energy concentrates. So the maximum intensity is found in space.