Tsvetan Velinov

Learn More
Surface plasmons are electromagnetic surface waves whose k vectors are greater than that of free-space radiation. We excite surface plasmons by using an oil-immersion lens, which forms one arm of an interferometer. We demonstrate the way in which the characteristic output variation with defocus is determined by the propagation properties of the surface(More)
Surface plasmons (SP's) are electromagnetic surface waves that propagate along the interface between conductors and dielectrics. The k vector of these waves is larger than the free-space wave vector. The importance of SP's lies in the fact that they are extremely sensitive to small changes in the dielectric properties of substances that are in contact with(More)
In this paper, we demonstrate how the confinement and enhancement of optical fields by surface plasmon resonance can allow non-linear microscopy to be performed in a simple, cost-effective widefield configuration, rather than the more usual laser-scanning arrangement. We present second harmonic and two-photon luminescence widefield images of dielectric and(More)
The photosynthetic changes evaluated by oxygen evolution, chlorophyll fluorescence, photoacoustics, and delayed fluorescence (DF) were studied in leaves of grown in vitro for 8 weeks grapevine plants (Vitis vinifera) infected by grapevine leafroll-associated virus 3 (GLRaV-3). The infected leaves were characterized during the viral infection without visible(More)
In this work a thick interface model is proposed in order to describe the photothermal signal perturbation introduced by grain interfaces. The validity of the model is discussed based upon photothermal reflectance microscopy results obtained on Fe sintered samples. A comparison with the thermal resistance model, which is valid only in the case of thin(More)
In this study, results are reported from guided-wave microscopy and imaging ellipsometry near the angle of resonant excitation of an optical guided mode in planar wave guides with metal and dielectric layers. The main goal was to test their ability to detect micro-organisms (Escherichia coli) attached to a support. For this purpose, images from the two(More)
  • 1