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• θ = angle of incidence (deg)
• θ_m = angle of diffraction of the mth order (deg)
• λ = wavelength of light (nm)
• τ = pulse delay time (ps)
• s = separation between two gratings used to compress a pulse (m)
• dθ_m/dλ = angular dispersion, or change in angle of diffraction with wavelength (deg/nm)
• (1/s)dτ/dλ = temporal dispersion, or change in pulse delay time with wavelength per meter of separation between two identical, parallel gratings (ps/nm per meter)