A pulse whose duration equals the minimum allowed by the Fourier transform of its spectrum, meaning all frequency components are in phase. The time-bandwidth product, duration times spectral width in frequency, is then about 0.441 for Gaussian and 0.315 for sech squared pulses. A measured product much higher than that shows residual chirp that more compression could remove.
Time-bandwidth product is 0.33 with a sech fit, so we're basically transform-limited and the compressor's done.
Also heard as
- Fourier-limited
- bandwidth-limited
- TL
Related terms
Chirp
A change in instantaneous frequency across a pulse, so its colors arrive spread out in time.
Pulse duration
How long a laser pulse lasts, normally given as the full width at half maximum of its intensity.
Autocorrelator
An instrument that measures ultrashort pulse duration by overlapping a pulse with a delayed copy of itself.
Linewidth
The spectral width of a single-frequency laser's output, usually given in Hz, kHz or MHz at half maximum.