We propose a new quantitative phase microscope based on spatial filtering of the beam carrying the sample-induced wavefront. A prototype built using a transmissive liquid crystal display for the experimental demonstration of the principle and preliminary results obtained with artificial and biological samples are presented.
A new method for the detection of light traversing a diffuser/nondiffuser interface and its simultaneous determination for optical tomography is proposed, and the preliminary results are shown. The method is based on the use of a point detector and two uncoupled scanning systems-one for illumination and the other for registration-together with active modification of the optics guided by the surface topography to generate virtual detectors on the interface.
We have developed a new prototype of a confocal scanning laser ophthalmoscope that incorporate relatively low-cost adaptive optics to correct for wavefront aberrations induced in the exit path of the eye and the optical setup components. The scanning part of the system consists of two galvanometric scanners, and the adaptive optics part contains a membrane deformable mirror in conjunction with a Hartmann-Shack wavefront sensor. The system allows to register images of the retina with infrared illumination at a 15 Hz frame rate and with a variable viewing angle in the range of 1° to 10°. We show first results obtained with the system with images of a test target in an artificial eye and with imaging of the living human retina. We compare images obtained without and with the adaptive optics part activated. In preliminary images, retinal features down to a size of ~25 μm have been resolved with the application of adaptive optics.
We propose a new version of the double pass apparatus with unequal entrance and exit pupil to measure the complete optical transfer function in the human eye. This system overcomes the limitation of the double pass technique with equal pupil sizes where phase information and odd asymmetries are lost in the double pass images (Artal, Marcos, Navarro and Williams, J.Opt.Soc.Am.A., 1995). By using the asymmetric double pass apparatus with different entrance and exit pupils, one of them small enough (usually the entrance pupil) to consider the eye diffraction limited, the complete optical transfer function of the eye, including the phase transfer function, and the shape of the point spread function are determined.