Chirped pulse amplification 2026-10-18
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Chirped pulse amplification increases an optical pulse's energy while keeping its peak power lower during amplification: stretch the pulse, amplify it, then compress it. A chirp is a changing instantaneous frequency. Stretching separates the arrival times of different frequencies; pulse compression brings their contributions back together. The gain medium supplies energy, whereas the compressor concentrates the surviving energy into a shorter time.
Donna Strickland and Gérard Mourou demonstrated chirped pulse amplification at Rochester in 1985. Their experiment used an optical fiber, a regenerative amplifier and a diffraction grating compressor.[ref]
Figure 1.
Stretch, add energy, then recover a short pulse
. Original functional chirped pulse amplification diagram using chosen Gaussian functions for pulse power. The common time axes show the stretching; each vertical axis has its own labelled scale. The idealized amplifier has flat optical gain across the occupied spectrum, and the compressor transmits 80 percent of the incident energy. These are teaching assumptions, not a reconstruction of the 1985 apparatus or a measured pulse trace. Details.
The useful idea is to arrange where the large peak power occurs. Lower light intensity in the amplifier reduces unwanted self-focusing and self-phase modulation; the compressed output can still drive strong nonlinear optics. Stretching does not remove every damage mechanism, and compression does not manufacture energy.
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