Making it unique and distinct from the known optical activity shown by gold, silver, silica nanopartcicles. Do alloys of them (gold, silver, silica) have scattering phenomenon like Lycurgus Cup?
The dichroic behaviour is mainly dependent on the intrinsic Surface plasmon property of a metal/dielectric interface. When the momentum of the incoming electrons or photons match that of the surface plasmons, the energy gets trapped by SPs leads to surface plasmon resonance (SPR). The optical excitation of SPR is mainly obtained by the total internal reflection (TIR) method. The P-polarized wave leads to the evanescent field that is exactly same form as that of the SPs. When the wave vector matches that of SPs, the light energy is transferred to SPs. As the wave vector of the evanescent wave can be adjusted by the incident angle, the excitation of SPs can be obtained by modulating the incident angle.
My view is that the long term white light irradiation increases the probability of the incident angle scanning leading to a dip in reflected light signals leading to the conversion of light into SPs, and the energy is absorbed is dissipates as the SPs propagate along the surface.
This paper could help you... http://link.springer.com/article/10.1007%2FBF03215599
@ Enrique Carbo-Argibay Thanks, The article above is good, further details I am looking for is in optical activity, any interaction among the alloys (gold, silver, silica) causes surface plasmon resonance, excitation and interaction of said nanoparticles for the distinct properties (reflection, transmission in light and dark) then the nanoparticles of the gold, silver, silica alone, any suggestion further is highly appreciated
Hey Prabhakar.... Optically the presence of plasmon layer on the colloidal nanoparticles surface act as anisotopic medium that induces a dichroic behaviour. Like in case of Lycurgus Cup, this anisotopic layer shows prominent light scattering phenomenon exhibiting red color in transmitted light and green color in light reflection.
Dear Subhra I accept the concept of anisotropy applied to lycurgus cup, reflection and transmission of light differ in colour property on the (prism like) nanoparticles with dichroic phenomena in anisotropic medium, what molecular interaction of atoms of metalic nanoparticles (Ag, Si, Au) are responsible for causing this behaviour any idea, Recently I got one paper in Springer http://link.springer.com/article/10.1007/s10853-014-8047-0/fulltext.html
Stating the dichroic phenomenon is mainly caused by localized surface plasmon resonance light scattering of large triangular prismatic and decahedral AgNPs"
as well as "dichroic property was observed in the samples irradiated with white light for a long time" How such time of white light irradiation will cause this phenomenon, instead excitation and relaxation of electrons in nanoparticles is instantaneous, do long term irradiation has a role here, any comment on these will be highly appreciated
The dichroic behaviour is mainly dependent on the intrinsic Surface plasmon property of a metal/dielectric interface. When the momentum of the incoming electrons or photons match that of the surface plasmons, the energy gets trapped by SPs leads to surface plasmon resonance (SPR). The optical excitation of SPR is mainly obtained by the total internal reflection (TIR) method. The P-polarized wave leads to the evanescent field that is exactly same form as that of the SPs. When the wave vector matches that of SPs, the light energy is transferred to SPs. As the wave vector of the evanescent wave can be adjusted by the incident angle, the excitation of SPs can be obtained by modulating the incident angle.
My view is that the long term white light irradiation increases the probability of the incident angle scanning leading to a dip in reflected light signals leading to the conversion of light into SPs, and the energy is absorbed is dissipates as the SPs propagate along the surface.
Nice answer Subhra, I totally agree with your explanation, views and opinions I just thought about dichroic phenomenon to be unique and interesting, and it was, further I got my doubt clear about reflection in day light and transmission in dark, thanks your suggestion were faithfully helpful.
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