Fourier optics is seen as an extension of Huygens-Fresnel rule. It is the survey of classical optics that involves the Fourier transforms. The political orientation behind this technique is that any moving ridge that is traveling has an infinite figure of moving ridge points which after clashing with an obstruction on the manner may be seen to take different waies from the original flight bespeaking that this moving ridge points are independent from each other i. e. a Franhoffer diffraction can be established from Fourier transforms. In Fourier transform technique when the moving ridge is near adequate it is really much possible to pay attending to the single moving ridge points.
Using mathematical computations in this measure basically explains the footing of Fourier analysis and synthesis. The Fourier analysis and synthesis usually explains the rules that are involved when light moving ridges pass through assorted slits or mirrors is to the full or partly reflected or curved one manner or the other. This technique forms the footing of the constructs that are involved in image processing techniques every bit good as its cardinal applications in light moving ridge state of affairss. Fourier optics is used largely as the conjugate of the spacial ( x. Y ) sphere for spacial frequence sphere ( kx. Bluegrass State ) .
In Fourier transform techniques. nomenclatures and constructs such as spectrum. bandwidth. transform theory. window maps and trying from one dimensional signal processing are used often. Materials and methods 1- A filter holder was placed in forepart of the beam expander and a 2-slit form selected. A 2-slit diffraction form was observed from a distance. 2- The simple screen was replaced with the photo-diode sensor assembly that was provided. This was sensor translated across the form and the strength distribution was captured by the package bundle. A package bundle called Science Workshop was used.
3- A lens was placed about 1 focal length beyond the slit system. The screen was moved until an image of the 2 slits was observed. At this phase the lens obeyed the lens equation 1/s +1/s’ = 1/f where s. s’ are object and image distances severally and degree Fahrenheit is the focal length of the lens. 4- Re-positioning was done for the screen so that it was 1 focal length beyond the lens and it was observed that the far-field ( Fraunhofer ) diffraction form of the 2 slits is now appeared. 5 – A 2nd lens was placed 1 focal length beyond the transform plane in order to reenforce the thought that a lens converts from existent infinite to Fourier infinite.
An scrutiny of the image formed 1 focal length beyond the 2nd lens was done and it was confirmed that it was so an image of the existent slit system. 6 – A figure of slit systems were provided so that an geographic expedition of their diffraction forms could be done in item. The strength forms of a figure of forms in both diffraction and existent infinite were recorded utilizing the Science Workshop package bundle. 7- Excel package bundle was used to cipher the Fourier transform of a 4-slit system. Comparisons were made between the 4-slit diffraction form with the graphical consequence of the Fourier transform.
Variations were done on the slit breadth / slit separation ratio and the effects on the associated diffraction form was examined. 9- As an debut to image filtering. a variable aperture was placed at the transform plane of the 1st lens when the 4-slit form being used. Mentions Pedrotti and Pedrotti Introduction to Optics ( 2nd Edition ) Prentice Hall 1993 Chapter 25. Hecht Optics ( 2nd Edition ) Addison – Wesley 1987 Chapter 11 and Section 14. 1. Scott. Craig ( 1998 ) . Introduction to Optics and Optical Imaging. Wiley.