We show, for the first time to our knowledge, how wavelength-scanning interferometry can be used to measure depth-resolved displacement fields through semitransparent scattering surfaces. Temporal sequences of speckle interferograms are recorded while the wavelength of the laser is tuned at a constant rate. Fourier transformation of the resultant three-dimensional (3-D) intensity distribution along the time axis reconstructs the scattering potential within the medium, and changes in the 3-D phase distribution measured between two separate scans provide the out-of-plane component of the 3-D displacement field. The principle of the technique is explained in detail and illustrated with a proof-of-principle experiment involving two independently tilted semitransparent scattering surfaces. Results are validated by standard two-beam electronic speckle pattern interferometry.
© 2005 Optical Society of America
(120.3180) Instrumentation, measurement, and metrology : Interferometry
(120.4290) Instrumentation, measurement, and metrology : Nondestructive testing
(120.5050) Instrumentation, measurement, and metrology : Phase measurement
(140.3600) Lasers and laser optics : Lasers, tunable
(170.4500) Medical optics and biotechnology : Optical coherence tomography
Pablo D. Ruiz, Jonathan M. Huntley, and Ricky D. Wildman, "Depth-resolved whole-field displacement measurement by wavelength-scanning electronic speckle pattern interferometry," Appl. Opt. 44, 3945-3953 (2005)