Selective excitation of a particular fluorophore in the presence of others demands clever design of the optical field interacting with the molecules. We describe the use of 20- to 50-GHz pulse-train excitation leading to two-photon absorption, followed by successive one-photon stimulated emission as a potential technique in the context of controlling two-photon molecular fluorescence, with appl...

Dye-protein fluoromodules consist of fluorogenic dyes and single chain antibody fragments that form brightly fluorescent noncovalent complexes. This report describes two new bichromophoric dyes that extend the range of wavelengths of excitation or emission of existing fluoromodules. In one case, a fluorogenic thiazole orange (TO) was attached to an energy acceptor dye, Cy5. Upon binding to a pr...

Arrays of sub-wavelength holes (nanoholes) in gold films were used as a substrate for enhanced fluorescence spectroscopy. Seven arrays of nanoholes with distinct periodicities (distances between the holes) were fabricated. The arrays were then spin-coated with polystyrene films containing different concentrations of the fluorescent dye oxazine 720. The dye was excited via resonant extraordinary...

Metallic nanoparticles (NPs) are able to modify the excitation and emission rates (plasmonic enhancement) of fluorescent molecules in their close proximity. In this work, we measured the emission spectra of 20 nm Gold Nanoparticles (AuNPs) fixed on a glass surface submerged in a solution of different fluorophores using a spectral camera and 2-photon excitation. While on the glass surface, we ob...

We develop a green light source with low spatial coherence via intracavity frequency doubling of a solid-state degenerate laser. The second-harmonic emission supports many more transverse modes than the fundamental emission, and exhibits lower spatial coherence. A strong suppression of speckle formation is demonstrated for both fundamental and second-harmonic beams. Using the green emission for...

Interactions between proteins can be demonstrated by fluorescence resonance energy transfer (FRET) [1]. The proteins under test must be fused with donor and acceptor molecules. At FRET energy is transferred non-radiatively from donor to acceptor. FRET can be detected in two ways: the change in emission-ratio between donor and acceptor can be measured, or the decrease in lifetime of the fluoresc...

The autofluorescence other than intrinsic protein emission of viable cultured mammalian cells has been investigated. The fluorescence was found to originate in discrete cytoplasmic vesicle-like regions and to be absent from the nucleus. Excitation and emission spectra of viable cells revealed at least two distinct fluorescent species. Comparison of cell spectra with spectra of known cellular me...

We present a decoupled fluorescence Monte Carlo (dfMC) model for the direct computation of the fluorescence in turbid media. By decoupling the excitation-to-emission conversion and transport process of the fluorescence from the path probability density function and associating the corresponding parameters involving the fluorescence process with the weight function, the dfMC model employs the pa...

Fluorescence and phosphorescence are listed as mineral optical–physical properties in classical gemology textbooks. The trace elements which exist gems, certain defects the crystal lattice, some luminous molecules contribute to luminescence phenomena gem materials, including fluorescence phosphorescence. A systematic study using an excitation-emission matrix (EEM) not only provides detailed inf...

Changes in fluorescence emission of the serum from patients with various cancers are characterized. The measurement of fluorescence emission of serum in the UVvisible range allows by estimation of NAD(P)H levels to monitor the alterations in energy metabolism, resulting from changes in the level of coenzymes in serum associated with neoplastic diseases. Introduction Over the past years, f luore...