title: Experimental study of the phenomenon of 1 x N spectral switch due to diffraction of partially coherent light.
abstract: Spectral properties of a class of partially coherent light with spectral profiles of varying bandwidths are studied on diffraction by a circular aperture in the far zone for different diffractive angles, i.e., for on-axis and off-axis points on the observation plane. It is found that the spectrum of the light in the far zone is different from that at the aperture plane. This change in the spectrum is termed spectral shift, which is found to be different at different diffractive angles. The spectral shift for a fixed diffactive angle shows a gradual change. However, for a critical value of the coherence at the aperture plane, the spectral shift shows a rapid transition, termed spectral switch. For different diffractive angles the coherence that causes the spectral switch also differs. Therefore the phenomenon of 1 x N spectral switch (consisting of one input port and N output ports) is studied experimentally.
authors.affiliation: Optical Radiation Standards, National Physical Laboratory, New Delhi, India.
authors.forename: Suman
authors.initials: S
authors.lastname: Anand
authors.forename: B K
authors.initials: BK
authors.lastname: Yadav
authors.forename: H C
authors.initials: HC
authors.lastname: Kandpal