Researchers demonstrated how they could use a quantum effect known as nonlinearity to modify and detect weak light signals. The development eventually could be used in personal electronics devices. But don’t expect to see a quantum gadget in Best Buy anytime soon. “The approach described in this article is relevant and exciting, but it appears to be far off from deployment,” Scott Hanson, the founder and chief technology officer of Ambiq, a firm that specializes in low-power devices, said in an email interview. “The chips used in today’s latest gadgets are based on roughly the same silicon-based ‘switches’ that have been around for decades. Even minor changes to the way these chips are manufactured take many years to deploy.”
Quantum Effects Lead to Discovery
The researchers used a new kind of semiconductor to create quantum dots arranged like an egg carton. The team produced this egg carton energy landscape with two flakes of semiconductor, which are considered two-dimensional materials because they are made of a single molecular layer, just a few atoms thick. Two-dimensional semiconductors have quantum properties that are very different from larger chunks, and could be used in low-power devices. “Researchers have wondered whether detectable nonlinear effects can be sustained at extremely low power levels—down to individual photons. This would bring us to the fundamental lower limit of power consumption in information processing,” Hui Deng, a physics professor and senior author of the paper in Nature describing the research, said in a news release. One key challenge the researchers had to overcome was how to control the quantum dots. To control the dots as a group with light, the team built a resonator by making one mirror at the bottom, laying the semiconductor on top of it, and then depositing a second mirror on top of the semiconductor. “You need to control the thickness very tightly so that the semiconductor is at the maximum of the optical field,” Zhang Long, a postdoctoral research fellow in Deng’s lab and first author on the paper, said in the press release. The new 2D semiconductors could bring quantum devices up to room temperature rather than the extreme cold that’s currently required. “We are coming to the end of Moore’s Law,” said Steve Forrest, an engineering professor and co-author of the paper, referring to the trend of the density of transistors on a chip doubling every two years, in the news release. “Two-dimensional materials have many exciting electronic and optical properties that may, in fact, lead us to that land beyond silicon.” If Deng’s research pays off, Ultra-Low Power Devices (ULPD) could be of enormous benefit to users, Charlie Goetz, CEO of Powercast, a wireless power company, said in an email interview. “They will enable ubiquitous IoT networks to be configured and deployed. These, in turn, will feed AI, which can then convert the quantity of input into quality output,” he added. “ULPDs will be the enabling factor that will drive—greener, safer, more efficient—smart cities of the future.”
Exploring Many Avenues to Low Power
Researchers are exploring a host of other technologies that could allow for ultra-low power devices. “There have been impressive advances in the System on a Chip (SoC) space these last few years,” Goetz said. “These low-powered devices can run for years on a battery and, more significantly, can be powered wirelessly at a distance using radio frequencies or in some cases, infrared.” The human race is swimming in batteries from smartphone to fire alarms, Hanson said. “This is quickly becoming unmanageable as our clothing, homes, and the cities around us all become ‘smart’ and ‘connected,’” he added. “For this to be sustainable, we must find a way to preserve battery lives—which means running electronics with less power. Technologies that accomplish this goal of ‘sipping less power’ are critical.”
