Photonics Spectra Preview - March 2022

Diode Lasers

Lidar technology is increasingly the core sensor technology for passenger vehicles with L2 or higher-level autonomy, leading to broader commercialization of the underlying laser technologies. Besides DPSS and fiber lasers, semiconductor lasers coupled with beam shaping optics have become the preferred solutions for automotive lidar thanks to their maturity, robust design, and comparatively low cost. In his article, FocusLight's Leon Li, examines progress in the two major types of semiconductor lasers for this application - edge-emitting lasers and VCSELs - as well as the optical beam shaping concepts designed to optimize their performance. Li will further discuss the comparative merits and general technology trends of different design concepts.

Key Technologies: semiconductor lasers, and specifically NIR diodes such as (GaAs based) edge-emitters and VCSELs, optical beam shaping for lidar systems, automotive lidar systems, DPSS lasers, fiber lasers

CMOS Imagers

Quanta Image Sensor technology first proposed in 2005 by Eric Fossum envisioned a large array of specialized pixels called jots that can accurately detect single photons at high resolution, high sensitivity, and at a very high frame rate. The technology promised to enable imaging capabilities that were previously impossible while overcoming the performance degradation associated with smaller pixel sizes. The concept has since evolved to include multi-bit QIS, where jots produce reliable photon number response beyond a single photon, allowing these sensors to be used in higher light scenarios without saturating the pixels. Gigajot discusses more recently developed QIS technology that utilizes this multibit QIS concept to achieve new sensor architectures with photon number resolution, sufficient photon capacity for high dynamic range imaging and capability to achieve competitive frame rates.

Key Technologies: photon counting, sCMOS sensors

CCD Cameras

Industries from telecom, Earth monitoring, GIS navigation, and others are rapidly multiplying the number of satellites in orbit. Often, these new satellites share a much smaller profile than those of a few decades ago, and they are frequently deployed en masse in constellations. While there are earthly benefits to these orbital platforms, they come at the cost of a growing volume of space debris. While the potential risk of collisions in Earth's vast orbit remains small, it is a growing risk and it is a potential threat to a growing number of extremely high-value space platforms. This has opened opportunities for new space-based monitoring platforms that employ CCD cameras - and specifically electron-multiplying CCDs) and lidar techniques to detect small fast-moving debris. Designed to deliver lower noise and faster imaging, these systems are aimed at mitigating the risk that space debris presents to orbital platforms. Emile Beaulieu of Nüvü Cameras highlights emerging developments in space debris monitoring and how the technology could soon be deployed to space.

Key Technologies: CCD cameras, ultra-sensitive EMCCD camera, lidar