Waveguides and devices
SOFT LITHOGRAPHY A technique belonging to the suite of SoftLithography, namely nanoimprinting, has been investigated by our group in order to produce Bragg grating
filters. These kind of devices are employed either as optical coupler and telecommunications filters (for the third optical window at 1500nm). Hybrid solgel titanium based
films (Ti/TMSPM) doped with a photosensitive agent have been employed for this aim. A Bragg grating is originally produced on this film by direct writing method based on
the interference generated by Lloyd mirror using the UV-line @364 nm of an Ar laser. Samples then undergo a development step with isopropyl alcohol and a densification
@160°C. Grating periods ranging from 2 mm down to 500 nm have been realized by selecting different angles of incidence on the mirror. From this master it has been
obtained a PDMS mold from which several replica have been produced by means of UV-nanoimprinting Either molds and replica have been characterized by means of AFM measurements. The following pictures show AFM results for a master whose grating periods is 500nm and its final replica on hybrid material. AFM measurements results for a master and its own replica. It is evident the almost exact reproduction of the peak height. |
References
- L. D'Amico, D. Colonna, R. De Angelis, M. Casalboni, F. De Matteis, A. Di Carlo, P. Prosposito
Bragg gratings nanostructuring of TiO2 layer in dye sensitized solar cells: an efficient method to enhance light harvesting
RSC Advances , 4(83), 43828-43833 (2014).
- D. Barettin, A. Di Carlo, R. De Angelis, M. Casalboni, P. Prosposito,
Effect of dielectric Bragg grating nanostructuring on dye sensitized solar cells
Opt. Expr. ,20 S6 A888 (2012).