2012 S3: Brittany Cooke

Generation of Diffraction Gratings Using Photographic Film

The properties of light is one of the most interesting and complex topics in physics.  For instance, multiple sources of light can interact with each other to create what are known as diffraction patterns – a series of alternating bright and dark spots.  These patterns can be produced from a single source of light by use of a diffraction grating.  A diffraction grating splits a source of light into multiple sources that can interact with each other.  Commercial diffraction gratings are generally made from etched glass. This project determines how well diffraction gratings can be made using an alternative method: photographic film.  This would give scientists a way to create diffraction gratings onsite rather than ordering them from another company.  Photographs of a diffraction grating pattern were taken and developed onto slide film. The slides were tested using a helium-neon laser and factors such as exposure (aperture size and time), focal length of the camera’s lens, and line spacing of the grating were tested for effectiveness.  Effective gratings were ones producing a clear diffraction pattern.

Faculty Mentor: Richard Vallery, Physics

1