Abstract
The method of caustics has been used for many years for studying deformations around crack tips in metals and other materials, but a systematic and easy-to-understand description of the principles and practice of photographing high quality caustics images has not been made available to potential practitioners of the method. This paper describes how sharp, high contrast caustic images can be obtained using simple equipment and procedures based on well-known principles of geometrical optics. The critical parameters are the light source diameter, which must be small, and its distance from the reflecting surface, which must be large; and high resolution, short depth of field and high initial magnification of the photographic system. Monochromatic filters or laser light sources can improve caustic images if the lens used is not highly corrected for chromatic errors. If collimated (parallel) light is desired to avoid making corrections for the divergence of the illumination, long focal length collimator lenses are necessary to minimize the light source diameter contribution to the caustic ring thickness.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.