US researchers develop light version of "dielectric antenna"

On July 13, 2015, the University of Wisconsin Madison announced that researchers at the University have developed a high-performance light-receiving/light-emitting element that has a cross-sectional area that is 10,000 times larger than the actual size of a component ( English publication materials, papers). The university stated that the device can be used as a light-receiving element with a light collection function, and will be developed for the realization of an ultra-high sensitivity light receiving element (PD), an ultra-high sensitivity imaging element using a PD, a high-efficiency solar cell, and an efficient heat-dissipating element. the way.

This component was developed by Professor Yuzong Fu of the Department of Electronics and Computer Engineering at the University of Wisconsin-Madison.

This new type of component can be said to be a light version of the "dielectric antenna." The dielectric antenna can transmit and receive electromagnetic waves having wavelengths much larger than those of its components with very small antenna elements. The specific structure of the new device is similar to that of a Fabry-Perot type laser device in which a high-refractive-index material layer having a thickness of 785 nm is sandwiched between two lenses. A light source or photodetector having a size of approximately 20 nm×110 nm is disposed on one lens, and a DBR (Distributed Bragg Reflector) layer is disposed on the other lens. The DBR layer has a structure in which Si layers and SiO2 layers are alternately arranged.

According to reports, newly developed components can transmit and receive infrared light with a wavelength of approximately 1.5 μm which is about 15 times larger than the size of the light receiver or light source. In addition, it can also send and receive light with a larger beam width, just as the component size reaches about 6 μm.

When this element is applied to a PD, the same effect as that of a light receiving element with a collecting lens can be obtained. In other words, it is possible to obtain a light collecting effect that is larger than the actual size of the light receiving element, and it is possible to increase the sensitivity of the light receiving element. In addition, when this element is applied to a solar cell, an effect like a concentrating solar cell can be obtained without using a large lens.

The research team is still considering implementing the reverse application of this component as an infrared radiator, that is, a component for radiation cooling. (Reporter: Nozawa Tetsuo)