LiDAR Design Lab: Wavelength

The longest range and most weather agnostic LiDAR wavelength is 1550nm.

All LiDAR sensors utilize a laser with a specific wavelength; each with its own unique physics constraints. Today’s LiDAR sensors (as well as tomorrow’s roadmap of sensors) are primarily 1550nm or 905/940nm. 1550nm offers superior performance over its 9xxnm counterparts in virtually every measure.

Eye Safety: Due to international eye safety standards, 1550 nm wavelength lasers can send 17x the number of photons out into the world than is allowed from those below 1000 nm (e.g. 905 nm, 940 nm). This means 1550 nm LiDAR has the potential for 17x resolution, 4x the detection range or some blend thereof as compared to a 9xx nm LiDAR.

Inclement Weather:LiDAR wavelength performance in weather is significantly more complicated than the other considerations covered here, but on the whole, 1550nm wavelength performs best overall - better than 905nm in humid air and scatter scenarios (e.g. fog), and significantly better than 940nm in humid air.

Solar Radiation:Significantly more sunlight reaches the Earth at 905 nm than 940 nm or 1550 nm, meaning the “floor” for detection of 905 nm systems is much higher than its counterparts. This provides a major sensitivity advantage to 1550nm and 940nm systems.

Production of 1550nm LiDAR uses parts developed specifically for the demands of the automotive use case, while 9xx nm was built on parts intended for consumer applications.

Different wavelengths require different semiconductor materials for detection. 9xx nm systems are detected by silicon (sand), a common single-element selected for its available thanks to the infrastructure of the camera semiconductor industry rather than its suitability for use in automotive applications. 1550 nm detection requires Indium Gallium Arsenide (InGaAs), an alloy consisting of less readily available materials that ultimately provide superior performance in automotive applications. Luminar has spent a decade developing the technology (backed by 200+ patents) and supply chain (now consolidated as Luminar Semiconductor, Inc.) to supply a product that truly meets the automotive industry needs – maximizing performance and reliability while minimizing cost.

For more information on the importance of wavelength, visit LiDAR Design Lab: Wavelength Whitepaper.