Ultrashort Pulse Dispersion Analyzer

Spectrum Definition

Gaussian Spectrum Sech² Spectrum Import From File

For Gaussian/Sech², this defines the spectral intensity shape $I(\omega)$ in the angular frequency domain.

Center Wavelength $\lambda_0$ (nm):

Bandwidth $\Delta\lambda$ (nm, Intensity FWHM): This is the FWHM of the intensity spectrum $I(\lambda)$. For Gaussian/Sech² shapes, it's converted to the FWHM in angular frequency $I(\omega)$ for internal calculations.

Spectral Phase

The spectral phase $\Phi(\omega)$ is Taylor expanded around the central angular frequency $\omega_0$ (derived from $\lambda_0$):
$$\Phi(\omega) = \phi_0 + \phi_1 (\omega - \omega_0) + \frac{1}{2!} \phi_2 (\omega - \omega_0)^2 + \frac{1}{3!} \phi_3 (\omega - \omega_0)^3 + \frac{1}{4!} \phi_4 (\omega - \omega_0)^4 + \dots$$

$\phi_0$ (rad) - Carrier-Envelope Phase (CEP):

$\phi_1$ (fs) - Group Delay (GD):

$\phi_2$ (fs²) - Group Delay Dispersion (GDD):

$\phi_3$ (fs³) - Third-Order Dispersion (TOD):

$\phi_4$ (fs⁴) - Fourth-Order Dispersion (FOD):

Simulation Grid

Grid Size N (2^Exponent): FFT points. Higher = more detail, slower.

Frequency Window Factor: Multiplier for spectral width ($\Delta\omega$) for FFT span. (Recommended: 1000 or higher for resolving fine spectral features).

Parameters

Spectrum Definition

Spectral Phase

Simulation Grid

Results