Farnaz Massoumian

Method for the generation of arbitrary complex vector wave fronts.

We describe an extremely versatile method that permits the accurate generation of arbitrary complex vector wave fields. We implement the scheme using a reconfigurable binary optical element that also permits additional fine tuning, such as aberration correction, to be performed. As examples we demonstrate the generation of both azimuthally and radially polarized beams.

Quantitative polarized light microscopy

We describe a simple modification to a confocal microscope, which analyses the state of polarization of light emerging from the specimen so as to permit quantitative polarized light microscopy to be performed. The system uses a novel form of rotating analyser which, together with lock‐in detection, permits images to be obtained where the image contrast corresponds to both specimen retardance and orientation (e.g. in the case of a birefringent specimen). Images are presented from a wide range of specimens and the origin of the contrast observed from simple point scatterers is investigated both theoretically and experimentally.

Generation and focusing of radially polarized electric fields

The use of radially polarized light is known to produce, when focused by a high-numerical-aperture objective lens, a spot of light whose polarization is predominantly axial. We have generated accurately such radially polarized fields, which we have coupled into a high-numerical-aperture microscope objective so as to produce an axially polarized focal spot.

Point spread functions with extended depth of focus

The use of an annular pupil plane filter may be used to increase the depth of focus of an objective lens without significant deterioration of the lateral resolution. However this approach is very inefficient since most of the illumination light is blocked by the annular filter. We describe a method which uses a diffractive optical element to increase significantly the depth of focus but with dramatically increased light efficiency.

A wavefront generator for complex pupil function synthesis

We describe a simple method to produce arbitrary complex optical fields using a computer generated binary phase hologram in a 4-f optical.

Pupil function engineering for confocal microscopy

The use of radially polarized light is known to produce, when focused by a high numerical aperture objective lens, a spot of light whose polarization is predominantly axial. We have generated radially polarized beams accurately and have confirmed this behavior experimentally and have also shown that the axial polarization leads to a ring type image of sub-resolution gold beads.