SERS of Dopamine: Computational and experimental studies.

Computational and experimental studies have been carried out on Dopamine. The calculated Raman spectra of Dopamine with and without Silver clusters (Ag (n = 1-4)) are compared with each other and it is shown that the intensity of the Raman activity increases with increasing number of silver atoms. The SERS effect shown by this system is further supported by calculating the Global electrophilicity index ω, the static mean polarizability α, and the anisotropy of the polarizabilities Δα.

Femtosecond laser fabrication of microfluidic channels for organic photonic devices.

We report on innovative application of microchannels with access holes fabricated by femtosecond laser irradiation followed by chemical etching. This technique allows us to demonstrate a novel approach to the achievement of organic photonic devices in which the properties of a conjugated polymer in solution are exploited in a microfluidic configuration to produce an easy-to-integrate photonic device. Filling the microchannel with a diluted polyfluorene solution, we exploit the unique properties of isolated polymeric chains such as ultrafast gain switching (switching response time of 150 fs) with a 100% on-off ratio.

Shape control of microchannels fabricated in fused silica by femtosecond laser irradiation and chemical etching.

We report on the fabrication of shape-controlled microchannels in fused silica by femtosecond laser irradiation at 600 kHz repetition rate followed by chemical etching. The shape control is achieved by suitable wobbling of the glass substrate during the irradiation process. Cylindrical microchannels with uniform cross-sections are demonstrated with an unprecedented length of 4 mm.