Prototype of a compact displacement sensor with a holographic diffraction grating

This paper discusses a compact displacement sensor which is constructed with a volume holographic diffraction grating. The sensor is integrated with a heterodyne interferometer. The best sensitivity can be better than 1 pm and the displacement error better than 28 nm within a traveling range of 2.5 mm. According to long-term static position observations, the stability of the proposed sensor is 10 times better than the apparatus to which it is compared. Furthermore, measurement of the thermal expansion properties of the hologram shows that the grating pitch variation is less than 0.1 nm as long as the temperature variation remains within 1 °C. Based on these results, the holographic diffraction grating has the potential to measure displacement with high sensitivity, high stability, and reduced measurement error.

► We proposed a prototype compact displacement sensor with holographic grating.
► The stability of the sensor is 10 times better than HP 5529 apparatus.
► The theoretical sensitivity is better than 1 pm.
► To preserve nano-metric displacement error within 2.5 mm traveling range.
► To demonstrate the thermal expansion property of the hologram (25–115 °C).