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Optical disk readout signals with a solid immersion lens (SIL) and the land-groove recording technique are calculated by use of a simplified vector-diffraction theory. In this method the full vector-diffraction theory is applied to calculate the diffracted light from the initial state of the disk, and the light scattered from the recorded marks is regarded as a perturbation. Using this method, we confirmed that the land-groove recording technique is effective as a means of cross-talk reduction even when the numerical aperture is more than 1. However, the top surface of the disk under the SIL must be flat, or the readout signal from marks recorded on a groove decays when the optical depth of the groove is greater than lambda/8.

The optical characteristics of a liquid-crystal (LC) panel with microdots on an electrode are investigated. Although 3 mum is larger than 1 molecule of LC material, microdots with a 3 microm diameter are sufficiently small to produce a smooth index profile. We use an electrode patterned in a new way to modulate the index profile of the LC panel, which allows us to modulate the optical phase of the passing light.

The author proposes a method to identify the three-dimensional positions of fluorescent biomarkers by recording just two images. In the proposed method, the x and y positions of all fluorescent markers are recorded in the first exposure, and the z positions are obtained from a blurred image in the second exposure. The author has verified this method using a specimen with 1 μm deep grooves and applied it to measuring chromatic aberration and the separation between two biological probes in fluorescence in situ hybridization cells. The method offers the advantage of greatly reduced data storage requirements.