Surface Enhanced Raman Spectroscopy of the plasmonic nanogratings obtained by Laser Induced Periodic Surface Structuring

Erkızan, Serena Nur
The research conducted in this study presents a novel method of generating highly sensitive Surface Enhanced Raman Spectroscopy (SERS) substrates by femtosecond laser writing techniques. Two different types of periodicity regimes are introduced by femtosecond laser-based nano-structuring of crystalline Silicon (Si) and generated patterns are classified as Low Spatial Frequency LIPSS (LSFL) and High Spatial Frequency LIPSS (HSFL). Quasi periodic, self-organized femtosecond laser written periodic nanostructures can embody required plasmonic gap distance, roughness and randomness to accommodate high hotspot density and enhancement factor of SERS. Silver (Ag) deposited nanoripples with different periodicity regimes exhibit state of art SERS enhancement factor as high as 10^9 with 10^-11 M limit of detection for Crystal Violet (CV) molecule. Enhancement factor dependence of the SERS substrates is investigated at Raman excitation wavelength 532, 660 and 785 nm. Raman enhancement factor simulations for all excitation wavelengths are performed by Finite Elements Method (FEM) based Maxwell solver by using COMSOL Multiphysics. Enhancement factor results obtained by measured SERS spectra and electric field enhancement simulations exhibit good agreement between them. A major advantage introduced by femtosecond laser-based SERS substrates is accurate and flexible control of processed region without restricting processing over large areas compared to well established top-down approaches such as nanoimprint lithography, electron beam lithography, chemical plasma etching. Fs-nanoripple generation do not require multiple processing steps like in nanoimprint lithography including stamp production of nanostructures, pattern transfer and peeling off. On the contrary of chemically synthesized and aggregated nanoparticle colloids, metal deposited quasi-periodic nanoripples offer reproducibility of obtained SERS signal over large areas and chemical stability for SERS aging measurements.


Laser induced periodic surface structuring for surface enhanced raman spectroscopy
Özkarslıgil, Zeynep Tuğçe; Bek, Alpan; Department of Physics (2020)
In this study, our aim is to fabricate and characterize efficient substrates of surface enhanced Raman spectroscopy (SERS) utilizing the field enhancement due to hot spots made by recently developed method of laser induced periodic surface structuring (LIPSS). LIPSS is a cost-effective technique for rapid processing of almost any materials compared to conventional lithography methods. Coating of a thin silver film on LIPSS applied substrate surface provides to observe the localized surface plasmon effect fo...
Akbıyık, Alp; Bek, Alpan; Department of Physics (2022-6-10)
In this thesis, Surface-Enhanced Raman Spectroscopy (SERS) substrates are fabricated using laser assisted chemical etching of silicon as a surface nanostructuring technique. As a novel method of control over the structuring parameters, the incident laser illumination is spatially modified via a Digital Micromirror Device (DMD) that enable fast and uniform fabrication of complex structures. Onto the photochemically nanostructured silicon surfaces, silver and gold films are deposited by thermal evaporation or...
Parameter estimation for instantaneous spectral imaging
Öktem, Sevinç Figen; Davila, Joseph M (2014-05-04)
Spectral imaging is a fundamental diagnostic technique in physical sciences with widespread application. Conventionally, spectral imaging techniques rely on a scanning process, which renders them unsuitable for dynamic scenes. Here we study the problem of estimating the physical parameters of interest from the measurements of a non-scanning spectral imager based on a parametric model. This inverse problem, which can be viewed as a multi-frame deblurring problem, is formulated as a maximum a posteriori (MAP)...
Concentric Ring Structures as Efficient SERS Substrates
Cinel, Neval A.; Cakmakyapan, Semih; Ertaş, Gülay; Ozbay, Ekmel (2013-05-01)
Plasmonic nanopatterned structures that can work as highly efficient surface-enhanced Raman scattering (SERS) substrates are presented in this study. A "coupled" concentric ring structure has been designed, fabricated, tuned, and compared to an "etched" concentric ring structure and plain gold film via SERS experiments. The proposed design gives Raman signal intensity 630 times larger than plain gold film and 8 times larger than an "etched" concentric ring structure. The surface plasmons were imaged with th...
Direct insertion probe mass spectrometry of polymers
Hacaloğlu, Jale (2012-04-16)
This chapter reviews advances in the technique of direct insertion probe mass spectrometry (DIP-MS) and its applications in polymer analysis for various purposes. The applications for thermal characterization involve investigation of the thermal stability, degradation products, and decomposition mechanism of complex polymer samples, in particular polymers involving flame retardants, polyphenylene- and poly(phenylene vinylene)-based materials, and coalesced homopolymers and polymer blends. Examples focused o...
Citation Formats
S. N. Erkızan, “Surface Enhanced Raman Spectroscopy of the plasmonic nanogratings obtained by Laser Induced Periodic Surface Structuring,” M.S. - Master of Science, Middle East Technical University, 2023.