Abstract

Light propagation induces remarkable changes in the spectrum of focused diffracted beams. We show that spectral changes take place in the vicinity of phase singularities in the focal region of spatially coherent, polychromatic spherical waves of different Fresnel numbers. Instead of the Debye formulation, we use the Kirchhoff integral to evaluate the focal field accurately. We find that as a result of a decrease in the Fresnel number, some cylindrical spectral switches are geometrically transformed into conical spectral switches.

© 2004 Optical Society of America

Gaussian imaging transformation for the paraxial Debye formulation of the focal region in a low-Fresnel-number optical system

Carlos J. Zapata-Rodrı́guez, Pedro Andrés, Manuel Martı́nez-Corral, and Laura Muñoz-Escrivá
J. Opt. Soc. Am. A 17(7) 1185-1191 (2000)

Focal shift in small-Fresnel-number focusing systems of different relative aperture

Yajun Li
J. Opt. Soc. Am. A 20(2) 234-239 (2003)

Spectral changes and spectral switches of partially coherent beams focused by an aperture lens

Liuzhan Pan and Baida Lü
J. Opt. Soc. Am. A 21(1) 140-148 (2004)

Effective Fresnel-number concept for evaluating the relative focal shift in focused beams

Manuel Martı́nez-Corral, Carlos J. Zapata-Rodrı́guez, Pedro Andrés, and Enrique Silvestre
J. Opt. Soc. Am. A 15(2) 449-455 (1998)

Debye representation of dispersive focused waves

Carlos J. Zapata-Rodríguez
J. Opt. Soc. Am. A 24(3) 675-686 (2007)