Wavelength: nm Incidence angle: deg Line density: lines/mm Grating separation: mm Diffraction order:

Start wavelength: nm End wavelength: nm Incidence angle: deg Line density: lines/mm Grating separation: mm Diffraction order:

This program computes the temporal dispersion introduced by a grating-pair compressor.
Function 1: compute the dispersion terms (phase, GD, GDD, TOD) at a single wavelength.
Function 2: compute the wavelength-dependent GDD and TOD over a wavelength range and plot the curves.

The dispersion terms of a double-grating compressor are:
$$\Phi = 2 \cdot \frac{2\pi}{\lambda} \cdot \frac{L_g}{\cos\theta} \left[1 + \cos(\gamma - \theta)\right] - 2 \cdot \frac{2\pi}{d} \cdot L_g \tan\theta$$
$$\frac{d\Phi}{d\omega} = 2 \cdot \frac{L_g}{c \cos\theta} \left[1 + \cos(\gamma - \theta)\right]$$
$$\frac{d^2\Phi}{d\omega^2} = -2 \cdot \frac{\lambda^3 L_g}{2\pi c^2 d^2} \cdot \frac{1}{\cos^3\theta}$$
$$\frac{d^3\Phi}{d\omega^3} = 2 \cdot \frac{3 L_g \lambda^4}{4 \pi^2 c^3 d^2} \cdot \frac{1 + \frac{\lambda}{d} \sin\gamma - \sin^2\gamma}{\cos^5\theta}$$
where $L_g$ is the grating separation, $\gamma$ is the incidence angle, $\theta$ is the diffraction angle, $d$ is the grating period, $\lambda$ is the wavelength, and $c$ is the speed of light.

[01] Nan Wang, PhD thesis, p. 58.