  Light emission is defined by its distribution in energy, momentum, and
polarization. Here, we demonstrate a method that resolves these distributions
by means of wide-angle energy-momentum spectroscopy. Specifically, we image the
back focal plane of a microscope objective through a Wollaston prism to obtain
polarized Fourier-space momentum distributions, and disperse these
two-dimensional radiation patterns through an imaging spectrograph without an
entrance slit. The resulting measurements represent a convolution of individual
radiation patterns at adjacent wavelengths, which can be readily deconvolved
using any well-defined basis for light emission. As an illustrative example, we
use this technique with the multipole basis to quantify the intrinsic emission
rates for electric and magnetic dipole transitions in europium-doped yttrium
oxide (Eu$^{3+}$:Y$_{2}$O$_{3}$) and chromium-doped magnesium oxide
(Cr$^{3+}$:MgO). Once extracted, these rates allow us to reconstruct the full,
polarized, two-dimensional radiation patterns at each wavelength.
