Temperature-tuned and excellent omnidirectional bending of light to the normal for energy concentration in an index-continuous structure

摘要

We present an alternative concept for omnidirectional bending of light and concentration of energy in an index-continuous structure, comprising two gradient-index SiO(x(0)(<=)(x)(<=)(2))layers and a thermochromic VO(2)layer. The concept helps to overcome the constraints of conventional optics that are nonadjustable and only functional at designed wavelengths. The advantages of both gradient-index and thermochromic materials are combined in this work to realize temperature-tuned omnidirectional concentration of energy. Using a double-coated ICS component of AIR/SiOx/SUB/SiOx/VO(2)for light manipulation and application near the visible spectrum range, this concept was numerically and experimentally demonstrated. The incoming light under oblique incident angles (0 degrees-80 degrees) was bent effectively and concentrated regardless of polarization. Favorable results demonstrated that a notably high energy concentration efficiencyP(e)(1.93-2.52) was achieved by varying the ambient temperatures (25-75 degrees C). This concept is general and can be applied in a variety of elements in light energy-efficient devices.