Dielectric mirror for broadband IR LEDs

LED devices and methods of operating LED devices are described. An LED device includes a light-emitting element, a wavelength converting layer and a dichroic mirror. The light-emitting element is configured to emit ultra violet, visible, or ultra violet and visible light. The wavelength converting layer is configured to absorb at least a portion of the light emitted by the light-emitting element and in response emit infrared light. The dichroic mirror transmits the infrared light emitted by the wavelength converting layer, reflects the light emitted by the light emitting element, and is arranged to reflect back into the wavelength converting layer light emitted by the light emitting element, transmitted unabsorbed through the wavelength converting layer, and incident on the dichroic mirror.