Self-imaging-based laser collimation testing technique

Improved collimation testing technique

“…Due to this small diameter, the laser beam cannot be used in some experiments, including optical image processing, optical imaging, Fourier transform generation, holography, optical data manipulation, free space communication, or optical quality inspection. Researchers in this area have proposed many techniques for collimation testing based on self-imaging [1][2][3][4][5][6][7][8][9][10][11][12][13]. We are suggesting an improvement of these techniques.…”

“…We are suggesting an improvement of these techniques. It is appropriate to give a brief introduction to the work mentioned in [1][2][3][4][5][6][7][8][9][10][11][12][13].…”

“…Different collimation testing techniques have been presented in literature, which may be classified as self-imaging techniques [1][2][3][4][5][6][7][8][9][10][11][12][13], interferometric techniques, and other specialized techniques. Selfimaging was first introduced by Silva [1] when he placed two identical gratings separated by the Talbot distance in the path of the beam and examined the resulting moiré fringe pattern.…”

“…When two gratings having spatial frequencies close to each other are overlapped, moiré fringes will appear. Most of the techniques [1][2][3][4][5][6][7][8][9][10][11][12][13] in collimation testing based on self-imaging use two identical gratings separated by the Talbot distance. This is the distance in coherent illumination where the image of the first grating illuminated with a collimated beam is produced at the position of the second grating separated by the Talbot distance.…”

“…1. Schematic diagram of modified optical system for collimation measurement [13]. lens2 is displaced a distance d on either side of its collimation position as shown in Fig.…”