Rainbows in the Grass. I. External Reflection Rainbows from Pendant DropletsApplied Optics
AbstractIn the mid-morning on a sunny day one can sometimes see glare spots associated with uncolored "rainbow" (i.e., fold) caustics due to the sunlight reflected from the surface of dew or guttation drops. We show that these dewdrop reflection rainbows are due to places on the droplet (i.e., from an "inflection circle") where its Gaussian curvature becomes zero. We work out the theory of such caustics with horizontally incident light and present a comparison of the theory to measurements made in the laboratory. (C) 2008 Optical Society of America
Publisher's StatementThis paper was published in Applied Optics and is made available as an electronic reprint with the permission of OSA. The paper can be found at the following URL on the OSA website: http://www.opticsinfobase.org/ao/abstract.cfm?URI=ao-47-34-H203. Systematic or multiple reproduction or distribution to multiple locations via electronic or other means is prohibited and is subject to penalties under law.
Citation InformationLock, James A., Charles L. Adler, and Richard W. Fleet. "Rainbows in the Grass. I. External Reflection Rainbows from Pendant Droplets." Applied Optics 47 (2008): H203-H213.