Liquid crystal meta-surfaces can steer lasers to create solid-state lidars for automotive and industrial applications, according to Lumotive of Seattle.

It claims a larger aperture for greater range compared to MEMS-based systems, and a technology that can be scaled for automotive, industrial and consumer use – with the surfaces manufactured in CMOS semiconductor processes.

“The huge challenge of lidar is balancing performance, characterised by range, resolution and frame rate, with commercial viability as measured by size, reliability and cost,” said Lumotive co-founder and CEO Dr William Colleran. “We’ve been able to achieve new levels in all these areas without significant compromise in any. We know that one size doesn’t fit all when deploying 3D sensing in different applications, and our underlying architecture allows us to scale the technology to meet specific market requirements while maintaining the cost benefits we achieve through our manufacturing approach.”

How does it work?

“Liquid crystals fill resonators on the metasurface,” Collean told Electronics Weekly. “When modulated by an electrical signal applied to the resonators, the liquid crystals change their index of refraction which in turn changes the amount of delay photons experience between entering the resonators and being re-emitted from the resonators. Consequently, each resonator acts as a programmable phase delay element.”

By applying an appropriate pattern of voltages across the meta-surface, an arbitrary phase profile can be created which results in a wavefront emanating from the meta-surface in the desired direction – an analogue of phased array radar.

The metasurface is illuminated from a known angle of incidence, and light reflects at a programmable angle of reflection.

Losses arise from two sources: some incident photons are converted to phonons (heat) and some photons exit at angles other than the desired angle of reflection.

“Efficiency, defined as optical power in the direction of interest divided by incident optical power, is improving rapidly as semiconductor processing improves,” said Collean.

Lumotive-X20-chipA liquid crystal meta-surfaces, manufactured in a CMOS semiconductor process

Samples of the Lumotive X20 automotive and Lumotive Z20 industrial automation lidars are scheduled to be available in the fourth quarter of this year, with introduction of the Lumotive’s M20 consumer and mobile lidar planned for 2021.

“These lidar systems integrate modules for transmit, receive and beam-steering, which may be purchased by automotive tier-1 suppliers and industrial sensor product vendors,” said Lumotive. “X20 targets automotive applications with range over 120m in bright sunlight and a 120° x 30° field of view. Z20 will have a ~50m range and a 70° vertical field of view to address industrial and short-range automotive needs.

Lumotive, founded in 2018, showed its X10 prototype at the CES trade show in Las Vegas this January.

The company website is here

Top image: X10 prototype (left) and a mock-up of the X20 commercial system, with a phone for scale.