scholarly journals Fibre Optic SERS Probes For Remote Sensing

2021 ◽  
Author(s):  
Aditya H. Pandya
Keyword(s):  
Remote Sensing ◽  
Raman Spectroscopy ◽  
Optical Fiber ◽  
Optical Fibers ◽  
Surface Enhanced Raman Spectroscopy ◽  
The Body ◽  
Periodic Array ◽  
Classification Model ◽  
Nanoporous Silica ◽  
Nanoporous Films

Surface Enhanced Raman Spectroscopy (SERS) enhances spontaneous Raman spectroscopy by the virtue of plasmon resonance of nanoparticles. Clinical application of SERS is challenging as nanoparticles remain in the body for long periods of time and a full toxicity analysis has yet to be extensively studied. In this study, Nanosphere lithography (NSL) was used to create optical fibers with nanoparticle enhanced tips for remote sensing using SERS. A custom designed RS collection setup was created for optimal collection of spectra from the optical fibers. It was found that an optical fiber with 0.5 numerical aperture (NA) allowed for better detection of Raman peaks while mitigating the fluorescence background of the optical fiber without any optical filters. Such a sensing platform can potentially be used to temporarily introduce nanoparticles into a sensing environment as it allows retracting the nanoparticles along with the tip. Nanoporous SERS platform has been fabricated using nanoporous silica glass with 7 nm and 17 nm pore diameters. An inexpensive fabrication approach of sputter deposition of Au layers was employed on prefabricated nanoporous silica glasses. 7 nm pore glasses provided larger enhancement than the glasses with 17 nm pores. A gold layer thickness of 25 nm was observed to produce largest enhancements. Nanoporous SERS substrates allow a larger effective SERS area compared to NSL based fabrication substrates and such nanoporous structures can be potentially fabricated on optical fiber tips for remote sensing. Finite Element Modeling (FEM) method was implemented for simulating single nanoparticles, an infinite periodic array of nanoparticles and nanoporous films using COMSOL Multiphysics software package. The extinction spectra obtained theoretically were found to match the experimental results for single nanoparticles. The maximum enhancement for the periodic array was two orders of magnitude larger than single particles while the integrated (average) enhancement was only two and a half times larger. Nanoporous films were also modelled using the FEM technique. Preliminary clinical data were collected from excised breast tissues for evaluating RS as a tool for cancer diagnostics. Spectral peaks from healthy tissues were found to be prominent than cancerous tissues and further experiments are needed to create a multivariate classification model for diagnostics.

scholarly journals Fibre Optic SERS Probes For Remote Sensing

2021 ◽  
Author(s):  
Aditya H. Pandya
Keyword(s):  
Remote Sensing ◽  
Raman Spectroscopy ◽  
Optical Fiber ◽  
Optical Fibers ◽  
Surface Enhanced Raman Spectroscopy ◽  
The Body ◽  
Periodic Array ◽  
Classification Model ◽  
Nanoporous Silica ◽  
Nanoporous Films

Surface Enhanced Raman Spectroscopy (SERS) enhances spontaneous Raman spectroscopy by the virtue of plasmon resonance of nanoparticles. Clinical application of SERS is challenging as nanoparticles remain in the body for long periods of time and a full toxicity analysis has yet to be extensively studied. In this study, Nanosphere lithography (NSL) was used to create optical fibers with nanoparticle enhanced tips for remote sensing using SERS. A custom designed RS collection setup was created for optimal collection of spectra from the optical fibers. It was found that an optical fiber with 0.5 numerical aperture (NA) allowed for better detection of Raman peaks while mitigating the fluorescence background of the optical fiber without any optical filters. Such a sensing platform can potentially be used to temporarily introduce nanoparticles into a sensing environment as it allows retracting the nanoparticles along with the tip. Nanoporous SERS platform has been fabricated using nanoporous silica glass with 7 nm and 17 nm pore diameters. An inexpensive fabrication approach of sputter deposition of Au layers was employed on prefabricated nanoporous silica glasses. 7 nm pore glasses provided larger enhancement than the glasses with 17 nm pores. A gold layer thickness of 25 nm was observed to produce largest enhancements. Nanoporous SERS substrates allow a larger effective SERS area compared to NSL based fabrication substrates and such nanoporous structures can be potentially fabricated on optical fiber tips for remote sensing. Finite Element Modeling (FEM) method was implemented for simulating single nanoparticles, an infinite periodic array of nanoparticles and nanoporous films using COMSOL Multiphysics software package. The extinction spectra obtained theoretically were found to match the experimental results for single nanoparticles. The maximum enhancement for the periodic array was two orders of magnitude larger than single particles while the integrated (average) enhancement was only two and a half times larger. Nanoporous films were also modelled using the FEM technique. Preliminary clinical data were collected from excised breast tissues for evaluating RS as a tool for cancer diagnostics. Spectral peaks from healthy tissues were found to be prominent than cancerous tissues and further experiments are needed to create a multivariate classification model for diagnostics.

Surface-enhanced Raman spectroscopy measurement of cancerous cells with optical fiber sensor

2014 ◽  
Vol 12 (s1) ◽  
pp. S13001-313003 ◽  
Author(s):  
Shupeng Liu Shupeng Liu ◽  
Lianxin Li Lianxin Li ◽  
Zhenyi Chen Zhenyi Chen ◽  
Na Chen Na Chen ◽  
Zhangmin Dai Zhangmin Dai ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Optical Fiber ◽  
Optical Fiber Sensor ◽  
Surface Enhanced Raman Spectroscopy ◽  
Fiber Sensor ◽  
Spectroscopy Measurement ◽  
Surface Enhanced ◽  
Surface Enhanced Raman ◽  
Cancerous Cells

Fitting an Optical Fiber Background with a Weighted Savitzky–Golay Smoothing Filter for Raman Spectroscopy

2018 ◽  
Vol 72 (11) ◽  
pp. 1632-1644 ◽  
Author(s):  
Jie Huang ◽  
Tielin Shi ◽  
Bo Gong ◽  
Xiaoping Li ◽  
Guanglan Liao ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Optical Fiber ◽  
Raman Spectra ◽  
Pearson Correlation ◽  
Similarity Index ◽  
Surface Enhanced Raman Spectroscopy ◽  
Sers Spectrum ◽  
Background Spectrum ◽  
Filter Model ◽  
Smoothing Filter

The Raman background arising from optical fiber materials poses a critical problem for fiber optic surface-enhanced Raman spectroscopy (SERS). A novel filter is developed to fit the optical fiber background from the measured SERS spectrum of the target sample. The general model of the filter is built by incorporating a weighted term of matching the similarity between the estimated background spectrum and the measured background spectrum into the classic Savitzky–Golay (SG) smoothing filter model. Through respectively selecting Euclidean cosine coefficient (ECos) and Pearson correlation coefficient (PCor) as the similarity index, two different models of the weighted SG smoothing filter are derived and named as SG-ECos and SG-PCor accordingly. Furthermore, the algorithm is presented, implemented, successfully applied to experimentally measured SERS spectra of rhodamine 6G and crystal violet, and validated with mathematically simulated Raman spectra. Experimental and simulation results show that the SG-ECos filter is effective, fast, flexible, and of certain anti-noise capability in background fitting. It is suggested that the proposed filter may be also applicable for other Raman spectra measurements to remove spectral contaminants originated from sampling substrates such as glass slides.

Matrix-Isolated Surface-Enhanced Raman Spectroscopy (SERS): The Role of the Supporting Matrix

1989 ◽  
Vol 43 (7) ◽  
pp. 1180-1187 ◽  
Author(s):  
Steven A. Soper ◽  
Theodore Kuwana
Keyword(s):  
Remote Sensing ◽  
Raman Spectroscopy ◽  
Detection Limit ◽  
Surface Enhanced Raman Spectroscopy ◽  
Solution Phase ◽  
Raman Spectrometer ◽  
Surface Enhanced ◽  
Surface Enhanced Raman ◽  
Tlc Plates

The influence of a supporting matrix in surface-enhanced Raman spectroscopy (SERS) has been investigated. The support matrices were conventional TLC plates onto which Ag colloidal hydrosols mixed with the dye pararosaniline had been deposited. The protocol of preparation of the Ag sol as well as the type of TLC plate had a profound effect upon the intensity of the SERS signals of pararosaniline. The Ag sol and the TLC plate that resulted in the maximum SERS intensities yielded a detection limit of ∼ 108 femtomols (33 pg) of dye deposited onto the TLC plate. Deposition of the dye/sol mixture onto the supporting matrix also resulted in stable SERS signals for extended periods of time, in contrast to the solution-phase case, where the signal is only transient in nature. In order to obtain the SERS spectra, a remote sensing Raman spectrometer was constructed and is described.

Raman Spectroscopy over Optical Fibers with the Use of a Near-IR FT Spectrometer

1988 ◽  
Vol 42 (8) ◽  
pp. 1558-1563 ◽  
Author(s):  
D. D. Archibald ◽  
L. T. Lin ◽  
D. E. Honigs
Keyword(s):  
Raman Spectroscopy ◽  
Optical Fiber ◽  
Optical Fibers ◽  
Scattered Light ◽  
Background Spectrum ◽  
Excitation Light ◽  
Analyte Signal ◽  
Near Ir ◽  
Potential Applications ◽  
Ft Ir

A commercial Fourier transform infrared (FT-IR) spectrometer was modified for remote near-IR Raman spectroscopy. In one configuration, a single optical fiber was used to guide the excitation light to the specimen and to collect scattered light from the specimen. In an alternative configuration, separate fibers were used for excitation and collection. The optical fiber probes were used to record the Raman spectra of both liquid and solid specimens. The Raman scattering of the optical fibers interfered with the analyte signal. This fiber interference was affected by the optical properties of the specimen and the optical sampling configuration. These interferences were partially removed by subtracting a background spectrum. Potential applications and improvements are discussed.

Periodic array of regular Ag nanoparticle trimers: a reliable polarization-independent surface-enhanced Raman spectroscopy substrate

RSC Advances ◽  
2016 ◽  
Vol 6 (86) ◽  
pp. 83273-83279 ◽  
Author(s):  
Chao Feng ◽  
Yan Zhao ◽  
Yijian Jiang
Keyword(s):  
Raman Spectroscopy ◽  
Surface Enhanced Raman Spectroscopy ◽  
Periodic Array ◽  
Ag Nanoparticle ◽  
Large Area ◽  
Surface Enhanced ◽  
Surface Enhanced Raman ◽  
Polarization Independent

A large-area periodic array of regular Ag nanoparticle trimers was fabricated, it possesses polarization-independent SERS performance.

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