Pulse Compressor
Adds a bounded second-order spectral-phase correction as positive or negative GDD. It can compress a pulse only by cancelling opposite accumulated GDD; higher-order phase and a physical grating, prism, or chirped-mirror layout are not modeled.
Open in the canvas →In the real world
An ultrashort pulse is shortest when its frequency components arrive with the spectral phase required by its transform limit. Material dispersion makes those components acquire different delays, producing chirp and a longer temporal envelope. A pulse compressor introduces the opposite spectral-phase curvature so the accumulated group-delay dispersion (GDD) approaches zero and the pulse becomes shorter again.
Real compressors commonly use diffraction-grating pairs, prism pairs, chirped mirrors, or combinations of them. Their geometry determines not only second-order GDD but also third- and higher-order dispersion, throughput, spatial chirp, and alignment sensitivity. The useful setting therefore compensates the measured upstream dispersion rather than having a universally correct negative value.
In OpticalSetup
The Pulse Compressor is a straight-through, zero-thickness GDD element. Set Applied GDD positive or negative; the value is added to every pulsed ray crossing its clear aperture, while transmission efficiency applies the configured loss. A negative setting compresses only when it cancels positive GDD already on the path — placed before any glass, the same negative magnitude broadens a transform-limited pulse instead.
For a transform-limited Gaussian source, the travelling packet overlay reads the local accumulated GDD along each traced segment. Its envelope grows continuously through catalogue glass and changes at the compressor, so the same pulse can be watched stretching and then returning toward its input length. The true duration, GDD, and stretch factor remain available numerically at a downstream detector.
This is a lumped second-order phase proxy, not a physical compressor prescription. It does not trace the compressor's internal grating, prism, or chirped-mirror geometry; it does not model carrier phase, third-order dispersion, spatial chirp, pulse-front tilt, nonlinear phase, or an independently authored input chirp. On-screen packet length is a qualitative glyph with an 8× display cap; detector numbers retain the unclamped second-order result.