Laser fabricated ripple substrates for surface‐enhanced Raman scattering

Abstract

Femtosecond laser fabricated surface nanograting structures, referred to as ripples, are proposed as efficient substrates for surface-enhanced Raman scattering (SERS). Ripple substrates show order of magnitude higher sensitivity and superior reproducibility as compared to lithographically made commercial SERS sensing substrates. It is demonstrated that the SERS intensity from ripple substrates scales with the thickness of the Au coating. Ag coating on sapphire ripples showed > 2000 times higher sensitivity as compared to the same coating on the flat sapphire surface. The period, duty cycle and aspect ratio of the ripple textures can be adjusted by laser ablation conditions, which could be used for plasmon resonance tuning.

Additional Enhancement of Electric Field in Surface-Enhanced Raman Scattering due to Fresnel Mechanism

“…This effect may be further exaggerated due to diffraction in the far-side excitation geometry. Although this is an interesting feature of the current results, it should not divert attention from further investigations of the angular dependence, as there are other SERS substrate geometries with higher dimensionality that provide a more consistent enhancement over a wider range of collection angles32.…”

Flexible periodical micro- and nano-structuring of a stainless steel surface using dual-wavelength double-pulse picosecond laser irradiation

“…That includes the control of surface wetting 7-9 , light extraction and harvesting 10,11 , chemical and mechanical alteration of materials 12 , colouring the surfaces 13-16 , nanotextured surfaces for bio-sensors [17][18][19] , micro-optical elements 20,21 and the light absorption enhancement [22][23][24][25] .…”

Nanoscale precision in ion milling for optical and terahertz antennas

“…SERS uses surfaces with structures which support LSPR at excitation laser frequency, usually it is lithography defined structures 17 or metal coated nanorough surfaces, such as black silicon 18 or ripples. 19 In terms of fabrication, randomly rugged surface can be easily obtained on large areas via dry ion etching or laser processing steps and is much cheaper as compared to lithography means. On the other hand, random surfaces give a bit lower repeatability than ordered and well defined ones.…”