The present invention relates generally to a laser beam through an optical diffuser that spreads out the beam for high spatial coherence, more particularly a device that increases the amount of spatial coherent light from a laser beam for horticulture. A user of the present invention will be able to manufacture a device which first spreads out a laser beam of coherent light with a diffuser, and then reflects the light that is generated by the internal reflections and refractions of the diffuser traveling along suboptimal trajectories back such that the amount of spatial coherent light toward target horticulture is magnified.
Spatial coherence is a strong correlation (fixed phase relationship) between the electric fields at different locations across the beam profile. For example, within a cross-section of a beam from a laser with diffraction-limited beam quality, the electric fields at different positions oscillate in a totally correlated way, even if the temporal structure is complicated by a superposition of different frequency components. Spatial coherence is the essential prerequisite for transmission holograms which can only be viewed by coherent light such as produced by a laser. The preservation of this coherent light is intended for advance plant growth (e.g., horticulture). To illuminate horticulture with coherent light an optical diffuser is deployed rather than a refractive lens system that would create an unwanted and potentially damaging burn area near the lens system.
Although this method of spreading a laser beam for illumination produces spread light with desired properties of spatial coherence, a significant amount of the light is lost. This loss is due to the fact that a portion of the light is internally reflected back and internally refracted back out of the diffusion material. This practice wastes energy and costs more for a return on the investment for a horticulture system to produce product.
Therefore, the object of the present invention is to employ a mirror to redirect light which would otherwise be lost. The present invention uses an arrangement of components that enable a laser beam to pass through a hole in a mirror to the optical diffuser. Once the beam enters the optical diffuser a portion of the light is directed backwards by the diffuser through internal reflection and refraction. However, because of the mirror the light which would normally be lost is directed back towards the optical diffuser. Using the diffuser to spread the source light, and the mirror to redirect wasted back light, increases the efficiency for the present invention to produce spatial coherence in a safe manner. Prior art of a system used for perceived white light is U.S. Pat. No. 9,683,730 “System and Method of Optimizing White Light” which uses a laser beam, diffuser, and modifying substrate to be excited to produce white light. This prior art system is edited to remove the modifying substrate and discovery was shown that the amount of light is increased with preservation of spatial coherence for a brighter transmission hologram thereby demonstrating more coherent light is available for horticulture use.
All illustrations of the drawings are for the purpose of describing selected versions of the present invention and are not intended to limit the scope of the present invention.
In reference to