Biomedical subjects

Michele Marrocco

Publications and source records attributed to Michele Marrocco.

3 recordsLinked to original sources

PubMed2005

Geometric determination of saturation in fluorescence spectroscopy.

In laser spectroscopy, saturation of atomic or molecular transitions cannot be ignored, even at modest laser intensities. The saturation status is customarily diagnosed from measurements of saturation curves describing the dependence of spectroscopic signals on laser intensity. I propose an alternative method that relies on a geometric comparison of the spatial laser profile with images of the spectroscopic quantity under investigation. A single image can be used to determine the saturation status and its associated saturation laser intensity.

Algorithms↗

PubMed2004

Fluorescence correlation spectroscopy: incorporation of probe volume effects into the three-dimensional Gaussian approximation.

Fluorescence correlation spectroscopy is a valuable tool in many scientific disciplines. In particular, such a spectroscopic technique has received a great deal of attention because of its remarkable potential for single-molecule detection. It is understood, however, that quantitative measurements can be considered reliable as long as molecular photophysics has been well characterized. To that end, molecular saturation and probe volume effects, which can worsen experimental accuracy, are treated here. These phenomena are adequately incorporated into the well-known three-dimensional Gaussian approximation by a novel method applied to interpret saturated fluorescence signals [Opt. Lett. 28, 2016 (2003)]. Comparisons with literature data are given to show the improvements of the suggested method compared with other approaches.

Journal Article↗

PubMed2003

Spatial laser-wing suppression in saturated laser-induced fluorescence without spatial selection.

Spatial wings of laser beams are of great concern in saturated laser-induced fluorescence. Their contribution to fluorescence is customarily avoided by resolution of laser peaks in the interaction volume. An alternative and versatile approach is formulated, based on the derivative of fluorescence with respect to laser intensity. It turns out that wing-free data are possible, although they are obtained from wing-dependent fluorescence. The advantages of this approach are exact centerline detection and simplicity of the experimental setup and procedure.

Journal Article↗