Optoelectronic chromatic dispersion in germanium PN photodiodes: wavelength monitoring and FBG interrogation.

Optoelectronic chromatic dispersion (OED) has recently been shown to be a significant source of chromatic dispersion in photodiodes. We characterize the OED in a commercial germanium PN-type photodiode and determine the optimum conditions for maximum OED sensitivity and wavelength monitoring. A peak OED sensitivity of 1 deg/nm is measured in a spectral range of 1550-1558 nm with 4 MHz modulation.

Directional Plasmonic Excitation by Helical Nanotips.

The phenomenon of coupling between light and surface plasmon polaritons requires specific momentum matching conditions. In the case of a single scattering object on a metallic surface, such as a nanoparticle or a nanohole, the coupling between a broadband effect, i.e.

Fluorescent Biotin Analogues for Microstructure Patterning and Selective Protein Immobilization.

Benzyl substitution on ureido nitrogens of biotin led to manifestation of aggregation-induced emission, which was studied by steady-state fluorescence, microscopy, and TD-DFT, providing a rationale into the observed photophysical behavior. Besides exhibiting solvatochromism, the biotin derivatives revealed emission peaks centered at ∼430 and 545 nm, which has been attributed to the π-π stacking interactions. Our TD-DFT results also correlate the spectroscopic data and quantify the nature of transitions involved.