Grating-Based Precision Measurement Systems

Grating-based precision measurement systems harness the predictable interaction of light with periodic structures to resolve displacements and angular deviations at sub-micrometre and microradian scales. Central to these systems is the diffraction grating: a surface etched or printed with evenly spaced lines or grooves that diffract an incident beam into multiple orders. By analysing the intensity or phase of diffracted orders, measurement schemes derive high-resolution displacement, angle or multi-degree-of-freedom information. Configurations range from linear encoders—where translational displacement is extracted from phase shifts—to autocollimators using diffracted spot arrays for angular determination, and interferometric arrangements that combine grating shearing, heterodyne or Michelson principles for simultaneous six-degree-of-freedom sensing. Scale gratings, fabricated by lithography or precision diamond cutting, underpin these sensors, offering large-area stability and low thermal drift. Recent innovations centre on metal–dielectric grating structures for polarisation-independent efficiency, two-dimensional encoders for multi-axis registration and frequency-comb-assisted schemes that expand dynamic range. Such systems find application in semiconductor lithography stages, coordinate measuring machines, precision robotics and astronomical instrumentation, where nanometre-scale control and repeatability are paramount, and where non-contact, high-bandwidth operation mitigates wear and backlash issues in mechanical contacting sensors.

Research from Nature Portfolio

No recent Nature Portfolio content available.

Research from all publishers

Recent developments in grating-based measurement from non-Nature Portfolio journals have advanced both sensor architectures and fabrication techniques. A 2025 study introduced a reflective two-dimensional metal–dielectric grating operated at a 45° azimuth, achieving over 95 % diffraction efficiency in both TE and TM polarisations; this structure demonstrated robust tolerance to manufacturing deviations and promises enhanced displacement mapping in two axes with a single grating element. Progress in lithographic fabrication was exemplified by a 2021 work on laser interference lithography: by deploying orthogonal and non-orthogonal two-axis Lloyd’s mirror interferometers, researchers produced large-area planar scale gratings with sub-nanometre pitch accuracy, critical for next-generation optical encoders serving multi-axis stages. In the realm of multi-axis sensing, a 2019 review highlighted grating reflector-based optical sensors combining autocollimation and planar encoders to measure three-axis translations and rotations with a single laser beam; integration of fast tool servo diamond cutting and interference lithography enabled large-area gratings, while Fizeau interferometry provided pitch verification, collectively reducing Abbe and misalignment errors for six-degree-of-freedom systems.

Grating-Based Precision Measurement Systems publication trend

The graph below shows the total number of articles in grating-based precision measurement systems across all publications each year (not limited to Nature Index journals).

Technical terms

Diffraction grating: A periodic structure that splits and diffracts incident light into discrete orders, enabling measurement of phase or intensity variations corresponding to displacement or angle.

Autocollimation: An optical technique in which a collimated beam is directed at a target reflector; angular deviations are inferred from lateral shifts of the returned beam or its diffraction orders on a detector.

Heterodyne interferometry: A method combining two beams of slightly different frequencies to generate a beat signal whose phase shift directly correlates with displacement.

Scale grating: A precision-fabricated grating used as a reference scale, commonly by lithography or diamond cutting, offering stable pitch standards over large areas for optical encoders.

Abbe error: A measurement error arising when the sensing axis is offset from the measurement axis, causing amplified uncertainty in multi-axis systems.

References

1. Auto-collimation diffraction of two-dimensional metal–dielectric grating with azimuth angle of 45°. Nanophotonics (2025).
2. Laser Interference Lithography for Fabrication of Planar Scale Gratings for Optical Metrology. Nanomanufacturing and Metrology (2021).
3. Optical Sensors for Multi-Axis Angle and Displacement Measurement Using Grating Reflectors. Sensors (2019).