Nano-structured surfaces by laser interference lithography and fs-laser direct writing as substrates for surface-enhanced Raman spectroscopy

2012 ◽  
Author(s):  
L. Ben Mohammadi ◽  
N. Hundertmark ◽  
F. Kullmann ◽  
F. Fleissner ◽  
T. Klotzbücher
Keyword(s):  
Surface Enhanced Raman Spectroscopy ◽  
Interference Lithography ◽  
Laser Interference Lithography ◽  
Direct Writing ◽  
Laser Direct Writing ◽  
Laser Interference ◽  
Structured Surfaces ◽  
Surface Enhanced ◽  
Surface Enhanced Raman ◽  
Fs Laser

scholarly journals Electromagnetic Modelling of Raman Enhancement from Nanoscale Structures as a Means to Predict the Efficacy of SERS Substrates

2007 ◽  
Vol 2007 ◽  
pp. 1-10 ◽  
Author(s):  
Richard J. C. Brown ◽  
Jian Wang ◽  
Martin J. T. Milton
Keyword(s):  
Surface Enhanced Raman Spectroscopy ◽  
Sers Substrate ◽  
Structured Surfaces ◽  
Nanoscale Structures ◽  
Sers Substrates ◽  
Raman Enhancement ◽  
Electromagnetic Modelling ◽  
Surface Enhanced ◽  
Surface Enhanced Raman ◽  
First Time

The requirement to optimise the balance between signal enhancement and reproducibility in surface enhanced Raman spectroscopy (SERS) is stimulating the development of novel substrates for enhancing Raman signals. This paper describes the application of finite element electromagnetic modelling to predict the Raman enhancement produced from a variety of SERS substrates with differently sized, spaced and shaped morphologies with nanometre dimensions. For the first time, a theoretical comparison between four major generic types of SERS substrate (including metal nanoparticles, structured surfaces, and sharp tips) has been performed and the results are presented and discussed. The results of the modelling are consistent with published experimental data from similar substrates.

scholarly journals Direct Fabrication of sub 100 nm Nanoneedles in Silver using Femtosecond Laser Direct Writing

2020 ◽  
Vol 70 (2) ◽  
pp. 197-200
Author(s):  
Venugopal Rao Soma ◽  
Balaji Yendeti
Keyword(s):  
Femtosecond Laser ◽  
Direct Method ◽  
Picric Acid ◽  
Numerical Aperture ◽  
Surface Enhanced Raman Spectroscopy ◽  
Direct Writing ◽  
Laser Direct Writing ◽  
Microscope Objective ◽  
Direct Fabrication ◽  
Surface Enhanced Raman

Novel methods for production of nanomaterials are urgently needed for various applications, especially in defence. In this work, we propose a direct method to produce silver nanoneedles using the femtosecond laser direct writing (LDW) technique. Femtosecond pulses were focused by a microscope objective on to a metal sheet to produce the nanoneedles. Nanoneedles of required dimensions were fabricated with a simple replacement of microscope objective of different numerical aperture. Further, we have investigated the effect of confinement. Finally, the application of nanoneedles is demonstrated for trace level detection of picric acid using surface enhanced Raman spectroscopy and a field deployable portable Raman spectrometer.

Bacterial detection and differentiation via direct volatile organic compound sensing with surface enhanced Raman spectroscopy

2017 ◽  
Author(s):  
Caitlin S. DeJong ◽  
David I. Wang ◽  
Aleksandr Polyakov ◽  
Anita Rogacs ◽  
Steven J. Simske ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Bacterial Infections ◽  
Direct Detection ◽  
Point Of Care ◽  
Surface Enhanced Raman Spectroscopy ◽  
E Coli ◽  
Recent Emergence ◽  
Surface Enhanced ◽  
Volatile Organic ◽  
Surface Enhanced Raman

Through the direct detection of bacterial volatile organic compounds (VOCs), via surface enhanced Raman spectroscopy (SERS), we report here a reconfigurable assay for the identification and monitoring of bacteria. We demonstrate differentiation between highly clinically relevant organisms: <i>Escherichia coli</i>, <i>Enterobacter cloacae</i>, and <i>Serratia marcescens</i>. This is the first differentiation of bacteria via SERS of bacterial VOC signatures. The assay also detected as few as 10 CFU/ml of <i>E. coli</i> in under 12 hrs, and detected <i>E. coli</i> from whole human blood and human urine in 16 hrs at clinically relevant concentrations of 10<sup>3</sup> CFU/ml and 10<sup>4</sup> CFU/ml, respectively. In addition, the recent emergence of portable Raman spectrometers uniquely allows SERS to bring VOC detection to point-of-care settings for diagnosing bacterial infections.

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