Ultracompact backlight-reversed concentration optics

We demonstrate a concentration scheme based on a reversed tracing concept utilizing a conventional sidelit backlighting configuration. The optical arrangement consists of a groove sheet and a wedge plate without any coating or surface treatment. The proposed layout simultaneously exhibits two main features: coupling the collimated solar radiance into a wedge plate and guiding the flux to the exit plane of the wedge plate for use in direct daylight. The measurement revealed an optical efficiency of 52% in conjunction with an inverse aspect ratio of 9.51. In addition to the two-dimensional sidelit scheme, the proposed structure can also be rotationally convolved and extended to a three-dimensional solar concentrator with a high concentration ratio, which will certainly have an impact on solar energy and other optical functions because of its simplicity and versatility.