Automated collimation testing by incorporating the Fourier transform method in Talbot interferometry

Abstract

In this paper, we report an automated technique for collimation testing by incorporating Fourier fringe analysis of the recorded interferograms in Talbot interferometry. The triangular profile of Talbot interferometric fringes has been recorded using a CCD and computer system. The interferograms corresponding to the in-focus, at-focus, and out-of-focus positions of the collimating lens have been recorded. Direct phase measurement using the Fourier transform method has been used for detection of collimation positions. Good accuracy and precision in measurement have been achieved.

Lissajous figure-based single-frame collimation technique

“…(13). The value of e 2 ± with this definition can be positive or negative depending on the ratio R 1 /R 2 .…”

“…Most of them are based on interferometry [1][2][3][4][5] or on self-imaging techniques [6][7][8][9]. In addition, several techniques have been proposed in the last years [10][11][12][13][14][15]. In particular, several collimation methods based on self-imaging that do not need a lateral displacement of the grating have been proposed, being these devices simple an stable.…”

Heterodyne moiré surface profilometry

“…The moiré measurement technique involves a simple optical apparatus; it is stable, economical, and can be used in a large measurement range; therefore, it has been widely employed in surface profile measurements [1,2], light beam collimation tests [3,4], autofocus tests [5], focal length measurements [6,7], and stress measurements [8,9]. In moiré surface profilometry, the information related to the tested surface profile can be recorded in the moiré fringes; thus, the capability of the moiré fringe analysis technique strongly affects the precision and resolution of the measurement, and whether the relevant information involved in the moiré fringes can be completely extracted.…”

Effective and flexible modeling approach to investigate various 3D Talbot carpets from a spatial finite mask

“…For example, Talbot interferometry allows to study the surface profile of transparent objects [3], the slope contours of bent plates [4] and also was used for collimation testing [5]. Additionally, the selfimaging properties of the Talbot effect are also suitable for sub-wavelength focusing of light [6] and offer new solutions for spectroscopy [7,8].…”