Teradar

In 1895, the German physicist Wilhelm Röntgen and his wife Bertha took the first recognizable x-ray: a ghostly image of her left hand. Their discovery changed the world forever, winning them the Nobel Prize. Over time, humanity leveraged their breakthrough use of non-visual wavelengths to exploit the vast majority of the electromagnetic spectrum—yielding groundbreaking inventions like the radio, radar and microwave ovens. But there has remained one segment of the electromagnetic spectrum, known as the terahertz gap, that eluded practical use.

Teradar, a startup whose three co-founders bridge radio, chip, and sensing innovation, has unlocked these last wavelengths in the service of a fundamentally new imaging technology: a terahertz imaging system, or “teradar,” ideally suited to automotive applications. Analogous to the development of radar (originally an acronym for “radio detection and ranging”), and lidar (“light detection and ranging”), Teradar’s technology enables a new category of device that combines the benefits of both. “To solve the problem of vehicle safety, we need a fundamentally new way of sensing things in real world environments,” says Teradar co-founder and CEO Matt Carey. “Using this last untapped chunk of the electromagnetic spectrum, we can see through rain and snow and fog, at high resolution and at low cost.” By making creative use of a custom chip fabrication process, Teradar packs its solid-state sensors into a credit-card-sized housing, creating a market-making new device affordable enough to be installed in everyday vehicles.

Terahertz waves combine the practical benefits of radar and lidar wavelengths. They are higher on the spectrum than radiowaves and microwaves, but lower than infrared and visible wavelengths. In automotive applications, today’s lidar can “see” at high resolution, but only in clear conditions. Lidar’s photons struggle when confronted with rain, snow, fog or dust, and its resolution drops out. Lidar also requires complex moving parts, significantly increasing both manufacturing and maintenance costs. Radar—in contrast—is cheap, and can see through weather. But despite decades of efforts by software and hardware engineers, radar’s fundamental physics still demand that sensor size increases with resolution—making high-resolution radars impractical on the inherently limited bumper real estate of passenger cars. Terahertz waves overcome both these challenges, allowing Teradar to reap the benefits of radar and lidar. ”Lower on the frequency spectrum, radar can see through weather, but at low resolution,” explains Carey. “Higher up on the spectrum, you get that resolution, but you can see through less.” Teradar’s terahertz wavelengths slip through fog droplets without degradation, providing a clear image—and a huge leap in automotive safety systems. “We’re at that Goldilocks frequency where we get the best of both worlds.”

Making the Teradar sensor practical and affordable required an unusual combination of photonic, radio, and chip innovation. Researchers had readily produced terahertz photons for decades, but struggled to do so at energy levels high enough for practical applications outside of the laboratory. Teradar co-founder Greg Charvat—author of Small and Short-Range Radar Systems, a standard textbook in the field—developed an innovative design that produced terahertz signals at the sweet spot for automotive applications: powerful enough to see out several hundred meters, but efficient enough for a broadly applicable product. Charvat had previously worked at Butterfly, a startup that pioneered ultrasound-on-a-chip, and applied that experience to the creative miniaturization of a terahertz system. Teradar’s third co-founder, Nick Saiz, adapted Charvat’s design to a highly specialized microchip fabrication process, more often used for satellite imaging systems. “This chip foundry allows us to access those higher frequencies at the efficiencies we need,” says Saiz. The proprietary design mixes techniques of radar, lidar, and infrared engineering, along with fundamentally new ideas, to unlock the terahertz band for automotive sensing.

The human ability to exploit the electromagnetic spectrum beyond what’s visible to the biological eye has driven untold technological revolutions. Now Teradar is opening a new space in the annals of its practical applications. “No one has ever successfully commercialized this terahertz gap before,” notes Carey. “Like the Röntgens, we’ve unlocked a new way of seeing. Except, instead of seeing through flesh and bone, we get the magical ability to cut through rain and snow and sleet and fog,” he adds. “And we can do that simply and inexpensively, fundamentally changing automotive safety, and saving tens of thousands of lives each year.”