An alignment technique based on the speckle correlation properties of Fresnel transforming optical systems

Abstract

The lateral correlation properties of speckle fields have been shown to be useful in aligning multiple optical channels relative to one another. Relative rotational alignment can also be achieved using a sub-sectioning extension of this technique. In this paper, we examine the three dimensional correlation properties of speckle, and by so doing, create a technique that allows for absolute positioning of a single channel free space optical system on the optical axis without the need for markers or gratings.

Three-dimensional static speckle fields Part II Experimental investigation

“…Furthermore, the existing experimental studies have not produced consistent results [7,8]. Recently, the longitudinal speckle size has been experimentally examined for Fresnel propagation and single lens linear canonical transform optical system cases, (see [9] and Chapter 8 in [10]). However, in [9,10] the theoretical expressions for the off-axis longitudinal speckle sizes are not consistent with the more physically accurate expression for jμ 12 j 2 , presented in Part I [1].…”

“…Recently, the longitudinal speckle size has been experimentally examined for Fresnel propagation and single lens linear canonical transform optical system cases, (see [9] and Chapter 8 in [10]). However, in [9,10] the theoretical expressions for the off-axis longitudinal speckle sizes are not consistent with the more physically accurate expression for jμ 12 j 2 , presented in Part I [1]. In Part II of this paper, the results of a detailed series of experiments are presented and compared to the analytic predictions presented in Part I [1].…”

K speckle: space–time correlation function of doubly scattered light in an imaging system

“…According to the Wiener-Khintchine theorem, we can digitally compute the correlation function using an FFT-based algorithm [30,31]:…”