I am also working on the development of a high-sensitivity nanoplasmonic sensor, consisting of nanoparticles either metallic or dielectric supported onto a flat substrate (glass), forming a single monolayer of nanoparticles randomly ordered. The whole system is sited over a prism (semi-cylindrical or pyramidal) with a matching index liquid in between, in order to disappear the glass-glass interface. The incident radiation is coming from inside the prism in a total-reflection configuration, thus the nanoparticles are illuminated by an evanescent wave. Since localized surface plasmons within the nanoparticles can couple an evanescent wave and convert it to a radiating one, the signal registered in the detector will be less that the expected if no particles are present (ideally the intensity coming out the source). The precise frequencies at which plasmons are excited can made the sensor highly sensitive and also tuneable by modifying the size and distribution of nanoparticles in the system.
Nowadays, exists several theories to model the reflectivity of a monolayer of particles, and thus a second objective of the project is to test and set the validity of such models. I´m collaborating with a well-known physicists, with a large experience in the field of electromagnetic waves interacting with colloidal systems, both theoretically and experimentally: Prof. Rubén G. Barrera and Prof. Augusto García-Valenzuela, additionally we are collaborating with Prof. Alipio G. Calles in numerical simulations part. In the experimental part we count with the expertise of Dr. Edgar Álvarez-Zauco and Dr. Arturo Rodríguez, as well with a very active group of students: Omar Vázquez (PhD student), Gesuri Morales-Luna (Master student). Recently Diana Pineda Vázquez started her undergraduate thesis in this topic.
