According to foreign media reports, researchers from Harvard University of Engineering and Applied Sciences used a new technology to induce the path of light, challenging the century-old law of light reflection and refraction. This technology is called phase discontinuity technology. This research discovery makes it possible to predict the path of light from one medium to another (for example, from air to glass), and a new mathematical law has emerged, which is different from the classical law of refraction and reflection. The research findings have been published in the latest Science magazine.

According to the joint team of Harvard University Engineering and Applied Sciences Applied Physics and Vinton Hayes Electrical Engineering Senior Research Fellows who participated in the study, the chief co-researchers are Professors Federico Capasso and Robert L. Wallace: Using a special plane, we created a flat funhouse mirror effect. Our discovery has brought optics into a whole new field and opened the door to exciting optoelectronics technology.

         Since the development of science and the understanding of the behavior of light, humans have known that light propagates at different speeds in different media. If light encounters a material such as glass and is incident at a certain angle, reflection and refraction will occur, and this is why the direction of the wavefront changes. Based on the traditional laws of refraction and reflection, we can deduce the behavior of light in physics classes all over the world. We can also calculate the specific values of the refraction angle and reflection angle based on the incident angle and the properties of the two media. However, when the researchers shined light on the structural diagram of the metal nanomaterial, based on the collision behavior of the surface light in the experiment, the researchers realized that the traditional equations were not enough to describe the phenomenon of the strange path of light observed in the laboratory.

        In the experiment, the researchers designed an array of nanoscale resonators, a little thinner than a wavelength, to create a constant gradient on the silicon surface. Using a visualization technique, the light can hit the surface partially and still remain perpendicular. The resonator on the left retains energy longer than the resonator on the right. However, without the entire array, the light is parallel.

         Through this Harvard study, scientists have also discovered a new law of light on a wide range of scales, which experimentally proves that this set of data is correct and will also confirm a new path between two media. According to Nanfang Yu, an associate researcher at the Capasso Laboratory for Engineering and Applied Sciences at Harvard University: Normally, near a pond, for example, the boundary between air and water forms two different paths. However, in this special case, the boundary between the medium and the medium becomes an active interface that can bend the light itself.

        The key to this research experiment is the use of tiny gold-plated antennas etched on the surface of silicon. The array structure is made very thin in overall scale, and the entire array structure is much thinner in scale than the wavelength of the light that hits it. This means that, from a traditional perspective, the boundary between the air and silicon in the optical system design gives a sudden phase shift, which is considered to be the manifestation of the second phase discontinuity.

        In the lab array, each antenna is a tiny resonator that can hold a specific amount of energy for a certain period of time without catching the light. Nanoresonators across the silicon surface have different types of gradients, which effectively bend light as it enters and begins to propagate through the new medium. The resulting strange phenomena break the old rules, creating light that can behave in arbitrary ways and appear to reflect and refract, depending on the pattern on the surface. To generalize the scientific laws of reflection and refraction to the newly discovered behavior of light, the Harvard researchers added some new design equations that can impart phase shift gradients. What's more, the new laws can be achieved to the extent that they are well known in the absence of surface gradients.

        According to Zeno Gaburro, a visiting scholar in the Capasso research group: By combining the phase discontinuous gradient with the interface, the laws of reflection and refraction of light become redefinable laws, and new phenomena appear. Reflected laser beams can be bounced away instead of forward, and negative refraction phenomena can be created, giving a completely new perspective on total reflection. In addition, the polarization of light can also be controlled, which means that an essential design definition occurs in the output of light. The researchers have successfully produced vortex beams, which are spiral-shaped light streams. They also envision flat lenses that can focus distortion-free images.