Research Projects

Origin: SERS enhancement relies on strong plasmonic near-fields localized around metallic nanostructures caused by surface plasmon resonance. Exact mechanism of high SERS and near-field dependence (reported to be E⁴) are still needs to be unveiled. While most of the studies are based on the designation of plasmonic substrates and single beam SERS measurements, no reports are available on the excitation of plasmonic near-fields separately and subsequent measurements to unveil exact influence of plasmonic near-fields. Use of single beam can not be the effective way of utilizing highest near-field and hence highest SERS contribution. A separate beam for SPR excitation is very much needed. Thus, a dual-beam pump-probe Raman can be considered as a potential candidate for high end SERS and can open new route for Raman probing (note: it is not CARS (Coherent Anti-Stokes Raman Scattering)). Novelty: In this project proposal novel dual-beam pump-probe near-field Raman methodology will be employed for ultra-sensitive SERS detection. The separate beam of appropriate wavelength will be used to excite SPR to cause huge-near-fields, and hence Raman scattering cross-section and signal. Objectives:  Design, computation and fabrication of cost effective highly sensitive hybrid plasmonic metasurfaces using soft lithography/interference lithography.  Development of dual-beam pump-probe near-field Raman, and ultra-sensitive SERS detection using hybrid plasmonic metasurfaces for food and health safety.  Understanding the physical origin of high SERS enhancement due to plasmonic near fields caused by surface plasmon resonance excitation by pump beam. Expected outcome/deliverables: Successful developments of dual-beam pump-probe near-field Raman may take a step ahead of ultrasensitive probing platform and understanding plasmonic near-fields dependence and further developments of effective SERS metasurface substrates. The development will potentially be applied in detecting SERS molecular finger printing and chemical analysis in various applied fields including food and health safety, forensic science, defence, biology, medical science etc. Novel design concept and ultrasensitive SERS detection, upon successful implementation, will have scientific outcome in the form of scientific papers and/or patents. Impact statement/Importance: Development of dual-beam pump-probe near-field Raman will have huge impact on the detection of Raman signal effectively, hence detection methodology. Furthermore, the proposed technique may explicitly be used to understand direct influence of near-fields on SERS enhancement. Methodology:  Hybrid plasmonic templates fabrication using soft-lithography/ interference lithography  Development of duel-beam pump-probe near-field Raman  SERS detection of Raman analytes for food and health safety using fabricated structures and duel-beam pump-probe near-field Raman Cost of the project: 48.7 Lakhs INR for 3 years