Wavelength-Multiplexed 2D Beam Steering via a Passive Diffractive Network
2026-06-15 • Computer Vision and Pattern Recognition
Computer Vision and Pattern RecognitionNeural and Evolutionary Computing
AI summaryⓘ
The authors designed a special type of optical device that uses different colors (wavelengths) of light to precisely control the direction of a 2D laser beam without moving parts or electronic phase controls. This device is made of multiple cleverly arranged layers that work together to steer light beams by changing the color, allowing many beam positions to be targeted independently. They tested their design both in computer simulations and real experiments across visible and terahertz light, showing it can quickly and accurately direct light in complex ways. This method could simplify and speed up applications needing precise beam steering like communication and sensing.
wavelengthdiffractive optical networkbeam steeringwavefront transformationdeep learning designspatial light modulatorterahertz frequenciesphase controloptical communicationsgratings
Authors
Che-Yung Shen, Yuhang Li, Cagatay Isil, Tianyi Gan, Mona Jarrahi, Aydogan Ozcan
Abstract
We introduce a wavelength-addressable diffractive optical network that transforms illumination wavelength into a high-dimensional control parameter for arbitrarily programmable 2D beam steering. The proposed passive architecture comprises cascaded spatially optimized diffractive layers, jointly designed using deep learning, to rapidly map distinct wavelengths to predefined/desired output angles. Unlike conventional single-layer dispersive optical elements, which are physically restricted to 1D linear mapping, this framework harnesses complex wavefront transformations to utilize the illumination wavelength as an intrinsic addressing key for arbitrary 2D beam steering, eliminating the need for mechanical scanning or electronic phase control. We numerically demonstrate wavelength-controlled beam steering across 625 wavelength channels spanning 400-750 nm, realizing a 25 x 25 array of independently addressable beam positions with subwavelength positioning accuracy and high channel fidelity. Unlike conventional gratings, which constrain wavelength routing to a linear trajectory, the proposed diffractive network performs nonlocal wavefront transformations, enabling arbitrary wavelength-to-angle mappings across a 2D field of view. We further validate the proposed framework experimentally in both the terahertz and visible spectral regimes, demonstrating wavelength-multiplexed beam steering using 3D fabricated passive diffractive layers at terahertz frequencies and phase-only spatial light modulators in the visible spectrum. This wavelength-addressable diffractive architecture establishes a compact and scalable paradigm for high-speed programmable beam steering, with potential applications in optical communications, routing, imaging, sensing, and emerging photonic information-processing systems.