Numerical investigations on photonic nanojet mediated surface enhanced Raman scattering and fluorescence techniques

Das, Gour Mohan; Ringne, Anil B.; Dantham, Venkata Ramanaiah; Easwaran, Raghavan K.; Laha, Ranjit

doi:10.1364/oe.25.019822

Cited by 44 publications

(19 citation statements)

References 36 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…It is to be noted that I PNJ is significantly more than I 0 = | E 0 | 2 , due to the large value of E Mie . Hence, in this arrangement, the Raman scattering signal enhances significantly and the expected enhancement of signal strongly depends upon the size and refractive index of the microsphere, numerical aperture of the objective lens, excitation wavelength, and surrounding medium refractive index …”

Section: Resultsmentioning

confidence: 99%

Enhancement of Raman scattering signal using photonic nanojet of portable and reusable single microstructures

Arya

Laha

Das

et al. 2018

J Raman Spectroscopy

Self Cite

View full text Add to dashboard Cite

We report the enhancement of Raman scattering signal for the first time using photonic nanojet of a lollipop‐shaped microstructure (LMS) fabricated with the help of a nanosecond CO2 laser. The LMS consists of a dielectric microsphere attached to a long stem/tapered fiber. The enhancement was achieved by focusing the incident laser light on sample surface through the microsphere of LMS. The experimentally observed enhancement was found to be comparable with that obtained from commercial microspheres that are not attached to any stems. The value of enhancement was found to increase with the microsphere diameter. The dielectric stems/tapered fibers alone of the LMS are found not efficient for enhancing the Raman scattering signals. In contrast to the commercial microspheres, the fabricated LMSs are easy to handle, portable, and reusable. Also, unlike commercial microspheres, these LMSs allow the enhancement of Raman scattering without modifying the surface of substrates containing sample. Hence, these LMSs are extremely useful in the case of photonic nanojet‐mediated surface‐enhanced Raman scattering and fluorescence techniques for enhancing the Raman scattering and fluorescence signals of single/few molecules, respectively.

show abstract

Section: Resultsmentioning

confidence: 99%

Enhancement of Raman scattering signal using photonic nanojet of portable and reusable single microstructures

Arya

Laha

Das

et al. 2018

J Raman Spectroscopy

Self Cite

View full text Add to dashboard Cite

show abstract

“…It is worth to mention here that the Eq. (5) assumes no plasmon coupling 54,55 between the sprouts. It is well known that size, shape and aggregation of particles lead to electric field enhancements differently 56 .…”

Section: Resultsmentioning

confidence: 99%

Enhancement of Single Molecule Raman Scattering using Sprouted Potato Shaped Bimetallic Nanoparticles

William

Das

Dantham

et al. 2019

Sci Rep

View full text Add to dashboard Cite

Herein, for the first time, we report the single molecule surface enhanced resonance Raman scattering (SERRS) and surface enhanced Raman scattering (SERS) spectra with high signal to noise ratio (S/N) using plasmon-active substrates fabricated by sprouted potato shaped Au-Ag bimetallic nanoparticles, prepared using a new one-step synthesis method. This particular shape of the nanoparticles has been obtained by fixing the amount of Au and carefully adjusting the amount of Ag. These nanoparticles have been characterized using scanning electron microscopy, extinction spectroscopy, and glancing angle X-ray diffraction. The single molecule sensitivity of SERS substrates has been tested with two different molecular Raman probes. The origin of the electromagnetic enhancement of single molecule Raman scattering in the presence of sprouted shape nanoparticles has been explained using quasi-static theory as well as finite element method (FEM) simulations. Moreover, the role of (i) methods for binding Raman probe molecules to the substrate, (ii) concentration of molecules, and (iii) Au-Ag ratio on the spectra of molecules has been studied in detail.

show abstract

“…Geometrical aspects have been mostly investigated in terms of microsphere size and objective that has been used . Several researchers have achieved the highest enhancement positioning the focus of the incident beam so that the width of the beam covered the sphere .…”

Section: Introductionmentioning

confidence: 99%

Photonic nanojet mediated Raman enhancement: Vertical Raman mapping and simple ray matrix analysis

Gašparić

Taccheo

Gebavi

et al. 2019

J Raman Spectroscopy

View full text Add to dashboard Cite

A new method for enhancing the Raman scattering signal has emerged recently, based on dielectric enhancement. Especially promising is the dielectric method based on microspheres and photonic nanojet. In this paper, geometrical aspects and the influence of the incident beam parameters on Raman enhancement by silica microspheres were systematically investigated in three steps: by characterizing the incident beam using knife-edge method, performing horizontal and vertical Raman mapping imaging, and analyzing the results using ray transfer matrix analysis. Maps show a distinct enhancement (hotspot) area caused by the microsphere photonic nanojet and lens effect compared to a plain silicon substrate. Enhancement value on maps was the highest (5.7×) for 0.50 numerical aperture objective, when the incident beam size matched the microsphere diameter, and the focus of the incident beam was below the top of the sphere, so that the output beam focus was at the microsphere-substrate contact area. This geometrical configuration was confirmed as ideal by performing simple ray transfer matrix analysis. The ideal ranges of incident and output beam parameters match with the measured hotspot area. This three-step process and the usage of vertical Raman mapping have been, for the best of our knowledge, performed for the first time in such configuration. This research introduces a new way of investigating microsphere-assisted Raman enhancement, offers different approach to microsphere optics research, and improves current knowledge of the influence of the incident beam on the enhancement.

show abstract

Numerical investigations on photonic nanojet mediated surface enhanced Raman scattering and fluorescence techniques

Cited by 44 publications

References 36 publications

Enhancement of Raman scattering signal using photonic nanojet of portable and reusable single microstructures

Enhancement of Raman scattering signal using photonic nanojet of portable and reusable single microstructures

Enhancement of Single Molecule Raman Scattering using Sprouted Potato Shaped Bimetallic Nanoparticles

Photonic nanojet mediated Raman enhancement: Vertical Raman mapping and simple ray matrix analysis

Contact Info

Product

Resources

About