Luminescence color multiplexing is one of the most intriguing benefits, which might occur by using semiconductor Quantum Dots (QDs) as labels for biomolecules. It was found, that the luminescence of QDs can be quenched, and replaced by a luminescence peak at approximately 460 nm on hybridization with certain regions of Arabidopsis thaliana tissue. This effect is site selective, and it is unclea...

Moonlit night scenes have a tinge of blue. Earlier work to model this perceptual effect has been statistical in nature; often based on unreliable measurements of blueness in paintings of moonlit night scenes. Needless to say there is a need of a more reliable and accurate model. We present a model based on the physiological functioning of the retina and how the rod and cone cells in the retina ...

The angular dependent reflection of a monodomain blue phase liquid crystal (BPLC) is investigated. Unlike a cholesteric liquid crystal with single twist structure, a monodomain BPLC exhibits several reflection orders from different crystal planes. As incident angle increases, the first order reflection experiences a blue shift while the second order experiences a red shift. We analyze the physi...

Multi-walled carbon nanotubes (MWCNT)-doped TiO2 thin films were synthesized by the dip-coating method. The obtained products were characterized by SEM, EDX, XRD, and UV-vis absorption spectroscopy. The XRD patterns showed the presence of anatase phase. Absorption spectrum of MWCNT-doped TiO2 revealed a red shift in the optical absorption edge due to carbon doping. The photocatalytic properties...

We have studied the blue shift in photoluminescence emission energy of pseudomorphic InGaAs/ GaAs quantum wells grown on patterned ~001! GaAs substrates with grooves and trenches having vertical sidewalls made by dry etching. Dependence of the blue shift, which can be as large as 51 meV, on the direction, feature size, and the etch depth of the patterns as well as the thickness of the buffer la...

The plasmonic behavior of size-selected supported silver clusters is studied by surface second harmonic generation spectroscopy for the first time. A blue shift of ∼0.2 eV in the plasmon resonance is observed with decreasing cluster size from Ag55 to Ag9. In addition to the general blue shift, a nonscalable size-dependence is also observed in plasmonic behavior of Ag nanoclusters, which is attr...

The 521-pigment extracted out of the retina of the Tokay gecko has the typical stereospecificity of the vertebrate visual pigments. This is true for the pigment in the chloride-depleted, "blue-shifted" state as well as for the normal pigment with added chloride. While in the chloride-deficient state, pigment regeneration occurred with both 11-cis- and 9-cis-retinals and the regenerated photopig...

Spectral tuning by visual pigments involves the modulation of the physical properties of the chromophore (11-cis-retinal) by amino acid side chains that compose the chromophore-binding pocket. We identified 12 amino acid residues in the human blue cone pigment that might induce the required green-to-blue opsin shift. The simultaneous substitution of nine of these sites in rhodopsin (M86L, G90S,...

In this article, I will discuss the optical properties of SiO2-nanoparticles that we have investigated recently by photoluminescence (PL) spectroscopy. In particular, I will show the blue-shifts of PL, originating from the electron-hole recombination of the self-trapped exciton (STE), observed in smaller-sized SiO2-nanoparticles. To explain the size effect in relating to the STE PL shift, a que...

We examine here the role of the red, green, and blue human opsin structures in modulating the absorption properties of 11-cis-retinal bonded to the protein via a protonated Schiff base (PSB). We built the three-dimensional structures of the human red, green, and blue opsins using homology modeling techniques with the crystal structure of bovine rhodopsin as the template. We then used quantum me...