Development of a multidimensional fluorometer and its application for authenticating objects marked with upconverting security markers.

We present a conceptual design of a multidimensional fluorometer, where a set of individually controlled laser diodes used as excitation light sources enables the user to obtain 3D spectra, i.e., excitation-emission matrices (EEMs), in a single measurement as well as acquire multidimensional spectra by scanning excitation and emission wavelengths and the power density and frequency modulation of excitation light.

Excitation-emission fluorimeter based on linear interference filters.

We describe the design, properties, and performance of an excitation-emission (EE) fluorimeter that enables spectral characterization of an object simultaneously with respect to both its excitation and its emission properties. Such devices require two wavelength-selecting elements, one in the optical path of the excitation broadband light to obtain tunable excitation and the other to analyze the resulting fluorescence. Existing EE instruments are usually implemented with two monochromators.

Formation of a resistive region at the anode end in DNA capillary electrophoresis.

We have studied the formation of a resistive region in the capillary during DNA separation. This effect is caused by an unequal change in the mobilities of cations and anions at the interface between the running buffer solution and the capillary. We studied the motion of the resistive region boundary by sequential removal of portions of the affected capillary end.

A family of novel DNA sequencing instruments based on single-photon detection.

We have developed a family of high-performance capillary DNA sequencing instruments based on a novel multicolor fluorescent detection technology. This technology is based on two technical innovations: the multilaser excitation of fluorescence of labeled DNA fragments and the "color-blind" single-photon detection of modulated fluorescence. Our machines employ modern digital and broadband techniques that are essential for achieving superior instrument performance.