ERIC Number: EJ859346
Record Type: Journal
Publication Date: 2009-May
Abstractor: As Provided
Reference Count: 2
Toal, Vincent; Mihaylova, Emilia M.
Physics Teacher, v47 n5 p295-296 May 2009
This note describes how white light interference fringes can be seen by observing the Moon through a double-glazed window. White light interferometric fringes are normally observed only in a well-aligned interferometer whose optical path difference is less than the coherence length of the light source, which is approximately one micrometer for white light. Obtaining such fringes in a Michelson interferometer is not a trivial task. The interferometer is typically illuminated with a monochromatic source and the path length difference adjusted with a wedge angle between the interferometer mirrors so that five or six vertical fringes are visible, indicating nearly equal paths. Then the mirrors are adjusted until the fringes are almost perfectly straight. Finally we use a white light source and carefully scan through the approximately equal path range until five or six white light fringes are seen to sweep rapidly by.
Descriptors: Optics, Physics, Science Instruction, Light, Laboratory Equipment, Science Laboratories, Astronomy
American Association of Physics Teachers. One Physics Ellipse, College Park, MD 20740. Tel: 301-209-3300; Fax: 301-209-0845; e-mail: firstname.lastname@example.org; Web site: http://scitation.aip.org/tpt
Publication Type: Journal Articles; Reports - Descriptive
Education Level: N/A
Authoring Institution: N/A