Far-field characterization of small apertures.
A far-field method for characterizing apertures based on the relationship between the relative intensity of propagating modes in a given medium and a small aperture illuminated with a light beam is proposed. A simple optical set-up based on computer-generated holograms and spatial filters is suggested to measure the relative strength of modes and provide axial intensity measurements in the far-field zone. It is shown that the minimal size of a spot that may be measured decreases with an increase in the refractive index of a medium into which light propagates and with the use of high-order spatial mode filters. The intensities transmitted through tapered optical fibre tips have been measured and their aperture diameters determined using window-type spatial filters. The results have been compared with measurements using scanning electron microscopy.
Petrov
N I
NI
Storage Laboratory, Samsung Advanced Institute of Technology, PO Box 111, Suwon 440-600, Korea. petrovni@mail.ru
Woo
G M
GM
Lee
M B
MB
D006696:Holography / Q000379:methods*; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D008853:Microscopy / Q000379:methods*; D008855:Microscopy, Electron, Scanning; D055095:Optics and Photonics