SMI Sensing

Ultra-low-power eye-motion tracking for AR wearables and 4D motion sensing for robotics.

A Physics-First Sensing Principle

Self-Mixing Interferometry (SMI) is a laser-based optical sensing technique that directly encodes motion and distance into the laser signal itself. Combined with machine-learning-enhanced signal interpretation, AlphaLum's SMI sensor delivers precise motion and distance sensing at a fraction of the power of traditional vision or 3D sensing systems. By "4D motion sensing," we mean continuous distance and velocity measurement over time—encoded directly in the optical signal and designed for always-on operation.

4D Motion Encoded in the Optical Signal

Unlike frame-based imaging, SMI Sensing encodes motion and distance directly into the laser's interferometric signal. Distance changes and velocity are captured at the source, eliminating the need for frame acquisition, feature tracking, or heavy downstream processing. Machine-learning models interpret the information-rich raw signal to deliver robust motion data.

Ultra-Low Power, Always-On by Design

Because SMI encodes motion directly in the laser signal, it operates without continuous imaging, frame acquisition, or feature extraction. This physics-first approach minimizes optical and computational load, enabling truly always-on motion sensing ideal for battery-constrained wearables and robotic systems.

Ultra-Compact Sensor Design

Our SMI Sensing element is small enough to integrate invisibly into the slimmest eyewear frames and compact sensing devices. This microscale footprint enables seamless integration without compromising product aesthetics or wearability.

Designed for Sensor Fusion

SMI Sensing provides additional advantages when fused with other sensors, e.g., cameras. It provides a parallel motion-sensing layer optimized for ultra-low-power operation. While cameras excel at scene understanding and semantic perception, SMI delivers continuous motion awareness without imaging — enabling hybrid sensing architectures that are more efficient, responsive, and privacy-friendly.

Technical Specifications at a Glance

Comprehensive capabilities for short-range high-precision motion sensing (Configurable Performance)

Why Add SMI to Your Sensing Stack?

Traditional Vision-Only Systems

Frame-based imaging with downstream compute
Latency introduced by vision pipelines
High power consumption for continuous operation
Sensitive to ambient light conditions

AlphaLum SMI

4D Motion: Distance and velocity encoded directly in the optical signal
Ultra-low power, always-on
Reduced compute load on vision systems
Works in any lighting condition

One Core Technology, Multiple Applications

A scalable optical sensing architecture supporting distinct motion-intelligence applications on the same foundational technology.

AR/VR Glasses

Eye motion and gaze dynamics (hybrid or camera-free architectures)
Attention-driven adaptive interfaces
Hands-free and implicit interaction
Privacy-friendly operation without continuous imaging
Enabling all-day wear within realistic power budgets

Robotics & Beyond

Simultaneous distance and velocity measurement
Spatial awareness in dynamic environments
4D motion feedback for control loops and collision avoidance
2D and 3D odometry and motion feedback
Robust operation across all lighting conditions

Start Your Integration

Explore how SMI motion intelligence can enhance your next product. We're partnering with early adopters to shape the future of optical sensing.