Three-wavelength electronic speckle pattern interferometry with the Fourier-transform method for simultaneous measurement of microstructure-scale deformations in three dimensions

Abstract

We present the simultaneous measurement of three-dimensional deformations by electronic speckle pattern interferometry using five object beams and three colors. Each color, corresponding to an orthogonal direction of displacement, is separated through dichroic filtering before being recorded by a separate CCD camera. Carrier fringes are introduced by tilting the beam path in one arm of each of the three interferometers. The measured deformation modulates these carrier fringes and is extracted using the Fourier-transform method to achieve high displacement sensitivity. The field of view is on the order of a millimeter, making the system suitable for study of microstructural deformations. We compare experimental results with calculated values to validate out-of-plane and in-plane deformation measurements and demonstrate sensitivity on the order of 10 nm.

Dynamic Characterization of Microcantilevers with a Shock Wave Excitation Method under High Temperature

“…methods need to integrate the embedded sensing elements, such as piezoresistive elements [6] and capacitive elements [7], into the microstructures. The non-contact optical methods, such as laser Doppler vibrometer (LDV) [8], stroboscopy and interferometry technique [9] and electronic speckle pattern interferometry (ESPI) [10], have several advantages over the BIST methods. Since there are no additional elements needed, the dynamic characteristics of the original microstructures will not be modified.…”

Online 3D Displacement Measurement Using Speckle Interferometer with a Single Illumination-Detection Path

“…To introduce different sensitivity vectors, an interferometric configuration with multiple illuminations and single detector is widely used. In this case, an online measurement can be realized by using spatial phase-shifting technique, together with, for example, the manipulation of the coherency of object and reference beams [ 22 ], or the control of the beams’ polarization [ 23 ], or the introduction of a multi-wavelength laser [ 24 ]. In addition, the ESPI systems with single illumination and multiple detectors for dynamic 3D displacement measurement have also been proposed [ 25 , 26 ], which, however, require a complex and elaborate calibration process.…”

Three-Dimensional Continuous Displacement Measurement with Temporal Speckle Pattern Interferometry

“…Flynn used five object beams and three colors to measure 3D deformations [2]. Each color was separated through dichroic filtering before being recorded by a separate CCD camera.…”