Speckle interferometric methods of measuring small out-of-plane displacements

Abstract

We present two new methods for measuring small out-of-plane displacement. These methods are descendents of Leendertz's method in speckle interferometry but provide fringes of good contrast.

Adaptive Bessel-autocorrelation of ultrashort pulses with phase-only spatial light modulators

“…In the latter caser, maps of correlation fringes are captured which represent a convolution of the information about phase profile and symmetry with the phase map of the reference wave (similar information is gained from phase dependent speckle patterns [10][11][12][13]). Because of their extraordinarily high sensitivity, these phase shift and phase step methods enable for monitoring even small specific phase changes caused by lasermaterial interaction, for example the dynamics of dephasing after coherent surface excitation [14].…”

Separation of the influence of in-plane displacement in multiaperture speckle shear interferometry

“…The irradiance distribution on the image plane for the first and second exposures, based on Eqs. (2) and (5), can be written as I = a + a + a + 2a1a2 cos(21 + 3) The phase differences a21, a32 and a31 are the same as defined in Eqs. (10) and (11) …”

Speckle photography and double aperture speckle interferometry using both sides of a suitably designed hololens imaging configuration

“…Optical measurement techniques are extensively used in experimental mechanics due to their non-contact nature [1]. A speckle-based measurement is one such optical technique for measuring in-plane displacement [2,3], out-of-plane displacement [4], tilt [5], stress [6], strains [7,8] and vibrations [9]. A speckle is a complex interference pattern, consisting of bright and dark spots randomly distributed in space, formed due to coherent illumination of an optically rough object [10].…”