| 摘要 |
Light sources and methods for spreading a beam of electromagnetic radiation. The light sources include a scattering element with an outlet and an angular-selective element with an inlet spatially disposed between the outlet of the scattering element and an electromagnetic radiation source. The beam enters the inlet traveling in a direction of propagation and propagates through the beam spreader to the outlet for transmission from the outlet. The scattering element includes a scattering medium configured to scatter the electromagnetic radiation in the beam to provide a two-dimensional spatial distribution for intensity that is substantially uniformly across the outlet. The angular-selective element is configured to reflect a majority of the electromagnetic radiation of the first beam scattered by the scattering medium in a direction opposite to the propagation direction and reaching the angular-selective element.
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