Surface patterning using speckle lithography for sers application

Laser speckles, a phenomenon caused when a laser reflects diffusely of a surface forming a granular pattern, is long considered as undesirable noise. In this project, the laser speckle effect is utilized to perform lithography to fabricate scattering substrates. Speckle lithography takes advantag...

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Main Author: Low, Zheng Ying
Other Authors: Murukeshan Vadakke Matham
Format: Final Year Project
Language:English
Published: Nanyang Technological University 2024
Subjects:
Online Access:https://hdl.handle.net/10356/177758
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Institution: Nanyang Technological University
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spelling sg-ntu-dr.10356-1777582024-06-01T16:54:17Z Surface patterning using speckle lithography for sers application Low, Zheng Ying Murukeshan Vadakke Matham School of Mechanical and Aerospace Engineering MMurukeshan@ntu.edu.sg Engineering Raman spectroscopy Laser speckles, a phenomenon caused when a laser reflects diffusely of a surface forming a granular pattern, is long considered as undesirable noise. In this project, the laser speckle effect is utilized to perform lithography to fabricate scattering substrates. Speckle lithography takes advantage of the laser speckles to form the target pattern, eliminating the use of an optical mask in conventional lithography. Initial simulations in ANSYS Lumerical were carried out to understand the effect of surface roughness in light localization. The simulations displayed a clear trend of increasing electric field intensity with increasing surface roughness. Optimization of the experimental parameters were then carried out by varying exposure time and power. Speckle patterns of different sizes were created by varying the laser spot size at the diffuser. The fabricated patterned surfaces are then used in Raman spectroscopy to test its effectiveness as SERS substrate. The results of the Raman spectroscopy confirm the findings from the simulations, where having higher surface roughness increases the intensity of Raman signals. This project gives insight into the ability of speckle lithography to fabricate scattering substrates over conventional lithography Bachelor's degree 2024-05-31T05:39:50Z 2024-05-31T05:39:50Z 2024 Final Year Project (FYP) Low, Z. Y. (2024). Surface patterning using speckle lithography for sers application. Final Year Project (FYP), Nanyang Technological University, Singapore. https://hdl.handle.net/10356/177758 https://hdl.handle.net/10356/177758 en B184 application/pdf Nanyang Technological University
institution Nanyang Technological University
building NTU Library
continent Asia
country Singapore
Singapore
content_provider NTU Library
collection DR-NTU
language English
topic Engineering
Raman spectroscopy
spellingShingle Engineering
Raman spectroscopy
Low, Zheng Ying
Surface patterning using speckle lithography for sers application
description Laser speckles, a phenomenon caused when a laser reflects diffusely of a surface forming a granular pattern, is long considered as undesirable noise. In this project, the laser speckle effect is utilized to perform lithography to fabricate scattering substrates. Speckle lithography takes advantage of the laser speckles to form the target pattern, eliminating the use of an optical mask in conventional lithography. Initial simulations in ANSYS Lumerical were carried out to understand the effect of surface roughness in light localization. The simulations displayed a clear trend of increasing electric field intensity with increasing surface roughness. Optimization of the experimental parameters were then carried out by varying exposure time and power. Speckle patterns of different sizes were created by varying the laser spot size at the diffuser. The fabricated patterned surfaces are then used in Raman spectroscopy to test its effectiveness as SERS substrate. The results of the Raman spectroscopy confirm the findings from the simulations, where having higher surface roughness increases the intensity of Raman signals. This project gives insight into the ability of speckle lithography to fabricate scattering substrates over conventional lithography
author2 Murukeshan Vadakke Matham
author_facet Murukeshan Vadakke Matham
Low, Zheng Ying
format Final Year Project
author Low, Zheng Ying
author_sort Low, Zheng Ying
title Surface patterning using speckle lithography for sers application
title_short Surface patterning using speckle lithography for sers application
title_full Surface patterning using speckle lithography for sers application
title_fullStr Surface patterning using speckle lithography for sers application
title_full_unstemmed Surface patterning using speckle lithography for sers application
title_sort surface patterning using speckle lithography for sers application
publisher Nanyang Technological University
publishDate 2024
url https://hdl.handle.net/10356/177758
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