An Ultracompact Angular Displacement Sensor Based on the Talbot Effect of Optical Microgratings

Abstract

Here, we report an ultracompact angular displacement sensor based on the Talbot effect of optical microgratings. Periodic Talbot interference patterns were obtained behind an upper optical grating. By putting another grating within the Talbot region, the total transmission of the two-grating structure was found to be approximatively in a linear relationship with the relative pitch angle between the two gratings, which was explained by a transversal shift of the Talbot interference patterns. The influence of the grating parameters (e.g., the grating period, the number of grating lines and the gap between the two gratings) was also studied in both a simulation and an experiment, showing a tunable sensitivity and range by simply changing the grating parameters. A sensitivity of 0.19 mV/arcsec was experimentally obtained, leading to a relative sensitivity of 0.27%/arcsec within a linear range of ± 396 arcsec with the 2 μm-period optical gratings. Benefitting from tunable properties and an ultracompact structure, we believe that the proposed sensor shows great potential in applications such as aviation, navigation, robotics and manufacturing engineering.

Combined Displacement and Angle Sensor with Ultra-High Compactness Based on Self-Imaging Effect of Optical Microgratings

“…Assuming that G1 and G2 have a relative displacement, the complex amplitude distribution behind G2 can be given [25] as follows:…”

“…In 2006, A. Wang et al reported a sensor that used the self-imaging effect to detect the local intensity and incident angle of light [24]. In 2022, Z. Yang et al reported an ultracompact angular displacement sensor using a double-grating structure with a sensitivity of 0.19 mV/arcsec within a range of ±396 arcsec [25]. Since both the linear and angular displacements are synchronously changing the amplitude of the output signal or the patterns of the selfimaging images in the cases mentioned above, the linear and angular displacements are hard to distinguish from each other.…”

Combined Displacement and Angle Sensor with Ultrahigh Compactness Based on Self-imaging Effect of Optical Microgratings

“…Assuming that G1 and G2 have a relative displacement, the complex amplitude distribution behind G2 can be given [25] ( ) ( ) ( )…”

“…In 2006, A. Wang et al reported a sensor that used the self-imaging effect to detect the local intensity and incident angle of light [24]. In 2022, Z. Yang et al reported an ultracompact angular displacement sensor using a double-grating structure with a sensitivity of 0.19mV/arcsec within a range of ± 396arcsec [25]. Since both the linear and angular displacement synchronously changing the amplitude of the output signal or the patterns of the self-imaging images in the cases mentioned above, the linear and angular displacement is hard to be distinguished from each other.…”