91ÅÝܽ

Synopsis

Lasers don’t just make steady beams of light — they can also fire pulses that last only femtoseconds, or even attoseconds. At these timescales, we can probe electron dynamics and even glimpse quantum vacuum effects. But this raises a dilemma: how do you measure something faster than any detector can respond? In this talk, we’ll start with the basics of how lasers, and especially pulsed lasers, work before diving into this measurement challenge. I’ll explain why autocorrelation, the classic method, only gives a partial answer, and then introduce Frequency-Resolved Optical Gating (FROG) — a powerful technique that reveals not just the duration, but the full shape and phase of ultrashort pulses. By learning how to capture these ultrashort bursts of light, we gain access to the very dynamics that shape our universe.