Abstract

Submicroscopic spider threads are used to support microscopic water droplets (9–60-μ diameter) in backscattering experiments with a 6328-Å laser. Van de Hulst’s analysis of the far-field radiance is modified to a near-field analysis and it is shown that the quantity C2/C1, which determines the radiance of the rings of the “glory,” can be obtained from measurements of the polarized components of the backscattered surface wave. For droplets with diameters between 9 and 15 μ, C2/C1 is 4.5±1.0, in agreement with Van de Hulst’s deduction from reported observations of the radiance and polarization properties of the rings formed by an artificial mist. The ratio of the radiance of the geometrical-optics contribution to the total backscattered radiance is measured vs droplet diameter; the measurements agree with Nussenzveig’s calculations at a size parameter of 130 (25-μ diameter). The results indicate that for droplets with size parameters larger than 370 (71-μ diameter), the backscattered radiance may be computed on the basis of geometrical-optics considerations alone. When the irradiation is limited to a cone of 2° semiangle, the geometrical-optics contribution is not visible for droplets smaller than 15 μ. For these small droplets, the entire radiance is due to surface-wave radiation.

© 1970 Optical Society of America

Full Article  |  PDF Article
OSA Recommended Articles
How are glories formed?

Philip Laven
Appl. Opt. 44(27) 5675-5683 (2005)

Complex angular momentum theory of the rainbow and the glory

H. M. Nussenzveig
J. Opt. Soc. Am. 69(8) 1068-1079 (1979)

Observability of atmospheric glories and supernumerary rainbows

James A. Lock
J. Opt. Soc. Am. A 6(12) 1924-1930 (1989)

References

You do not have subscription access to this journal. Citation lists with outbound citation links are available to subscribers only. You may subscribe either as an OSA member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access OSA Member Subscription

Cited By

You do not have subscription access to this journal. Cited by links are available to subscribers only. You may subscribe either as an OSA member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access OSA Member Subscription

Figures (9)

You do not have subscription access to this journal. Figure files are available to subscribers only. You may subscribe either as an OSA member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access OSA Member Subscription

Equations (24)

You do not have subscription access to this journal. Equations are available to subscribers only. You may subscribe either as an OSA member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access OSA Member Subscription