An energy scattering layer (110, 162, 600), comprising: a plurality of substantially-transparent particles; and a substantially-transparent matrix material that fixes the particles in a layer arrangement to form an energy scattering layer, characterized in that: the energy scattering layer has an energy-incident side, and the particles are fixed in the matrix material in a manner that causes the layer arrangement to reflect substantially all of one or more selectable wavelengths of incident energy impinging on the energy scattering layer from the energy-incident side, pass other wavelengths of the incident energy through the energy scattering layer, and an index of refraction of the layer arrangement is adjusted to reflect the one or more selectable wavelengths of incident energy, wherein at least some of the particles are fixed in the matrix in a manner that leaves voids between adjacent ones of the at least some of the particles through which the other wavelengths of incident energy pass through the energy scattering layer, and at least some of the voids penetrate an entire thickness of the energy scattering layer. a plurality of substantially-transparent particles; and a substantially-transparent matrix material that fixes the particles in a layer arrangement to form an energy scattering layer, characterized in that: the energy scattering layer has an energy-incident side, and the particles are fixed in the matrix material in a manner that causes the layer arrangement to reflect substantially all of one or more selectable wavelengths of incident energy impinging on the energy scattering layer from the energy-incident side, pass other wavelengths of the incident energy through the energy scattering layer, and an index of refraction of the layer arrangement is adjusted to reflect the one or more selectable wavelengths of incident energy, wherein at least some of the particles are fixed in the matrix in a manner that leaves voids between adjacent ones of the at least some of the particles through which the other wavelengths of incident energy pass through the energy scattering layer, and at least some of the voids penetrate an entire thickness of the energy scattering layer. the energy scattering layer has an energy-incident side, and the particles are fixed in the matrix material in a manner that causes the layer arrangement to reflect substantially all of one or more selectable wavelengths of incident energy impinging on the energy scattering layer from the energy-incident side, pass other wavelengths of the incident energy through the energy scattering layer, and an index of refraction of the layer arrangement is adjusted to reflect the one or more selectable wavelengths of incident energy, wherein at least some of the particles are fixed in the matrix in a manner that leaves voids between adjacent ones of the at least some of the particles through which the other wavelengths of incident energy pass through the energy scattering layer, and at least some of the voids penetrate an entire thickness of the energy scattering layer. reflect substantially all of one or more selectable wavelengths of incident energy impinging on the energy scattering layer from the energy-incident side, pass other wavelengths of the incident energy through the energy scattering layer, and an index of refraction of the layer arrangement is adjusted to reflect the one or more selectable wavelengths of incident energy, wherein at least some of the particles are fixed in the matrix in a manner that leaves voids between adjacent ones of the at least some of the particles through which the other wavelengths of incident energy pass through the energy scattering layer, and at least some of the voids penetrate an entire thickness of the energy scattering layer.