basilwong/laser-diffraction-analysis

Compares the single slit laser diffraction results with Fraunhofer and Fresnel Diffraction Models.

Laser Diffraction Analysis

This class is for analyzing the intensity spectrum for a laser going through a single slit aperture. Using this class the intensity spectrum can be compared with the Fraunhofer and Fresnel Diffraction models.

Setup

Clone this repository using the terminal command:

git clone https://github.com/basilwong/laser-diffraction-analysis.git

Add all (python package)dependancies using the terminal command:

pip install -r requirements.txt

Use Example

import diffractiondata

analyzer = diffractiondata.DiffractionData("example-photos//11.25.jpg", True, slit_width=0.5e-3)
analyzer.plot_picture_data()

The result of the above code can be viewed as below:

Background

In the sections below the equations governing the Fraunhofer and Fresnel models are defined for a single slit aperture with a screen behind it.

To preface the data below, the represents “nearness” of a diffraction pattern. In general, the Fresnel limit is the better model for large while the Fraunhofer limit is the better model for .

The equation for is as below:

• w is slit width
• R is distance to the screen, which in this case is 364 cm.
• λ is the wavelength of the laser

Fresnel Model

The Fresnel model is the generalized version of the Fraunhhofer model.

To get the Fresnel Model we use the equations defined by Equation 12.76 in "Classical and Modern Optics" by Daniel A. Steck as below:

Where:

Fraunhofer Model

The Fraunhofer model is obtained in the limit of . The resulting equation is as below: