Enhancement of Raman Scattering using Photonic Nanojet and Whispering Gallery Mode of a Dielectric Microstructure

We report the enhancement of Raman scattering
signal by one order of magnitude using photonic nanojet (PNJ) of a
lollipop shaped dielectric microstructure (LSDM) fabricated by a
pulsed CO₂ laser. Here, the PNJ is generated by illuminating sphere
portion of the LSDM with non-resonant laser. Unlike the surface
enhanced Raman scattering (SERS) technique, this technique is
simple, and the obtained results are highly reproducible. In addition,
an efficient technique is proposed to enhance the SERS signal with
the help of high quality factor optical resonance (whispering gallery
mode) of a LSDM. From the theoretical simulations, it has been
found that at least an order of magnitude enhancement in the SERS
signal could be achieved easily using the proposed technique. We
strongly believe that this report will enable the research community
for improving the Raman scattering signals.

Authors:

• A. Arya
• R. Laha
• V. R. Dantham

Keywords:

• Localized surface plasmons
• photonic nanojet
• SERS
• whispering gallery mode.

References:

[1] K. Kneipp, M. Moskovits, H. Kneipp, Surface-Enhanced Raman
Scattering: Physics and Applications (Springer, Berlin, 2006).
[2] K. J. Yi, H. Wang, Y. F. Lu, and Z. Y. Yang, “Enhanced Raman
scattering by self-assembled silica spherical microparticles” J. Appl.
Phys. 101, 063528 (2007).
[3] C. L. Du, J. Kasim, Y. M. You, D. N. Shi and Z. X. Shen,
“Enhancement of Raman scattering by individual dielectric
microspheres” J. Raman Spectrosc. 42, 145 (2011).
[4] V. R. Dantham, P. B. Bisht, and C. K. R. Namboodiri, “Enhancement of
Raman scattering by two orders of magnitude using photonic nanojet of
a microsphere” J. Appl. Phys. 109, 103103 (2011).
[5] J. F. Cardenas, “Raman scattering enhancement by dielectric spheres” J.
Raman. Spectrosc. 44, 540 (2013).
[6] Y. Yan, C. Xing, Y. Jia, Y. Zeng, Y. Zhao, and Y. Jiang, “Selfassembled
dielectric microsphere array enhanced Raman scattering for
large-area and ultra-long working distance confocal detection.” Opt.
Express 23, 25854 (2015).
[7] Z. Chen, A. Taflove, and V. Backman, “Photonic nanojet enhancement
of backscattering of light by nanoparticles: a potential novel visible-light
ultramicroscopy technique” Opt. Express 12, 1214 (2004).
[8] S. Lecler, Y. Takakura, and P. Meyrueis, “Properties of a threedimensional
photonic jet” Opt. Lett. 30, 2641 (2005).
[9] A. V. Itagi, and W. A. Challener, “Optics of photonic nanojets” J. Opt.
Soc. Am. A 22, 2847 (2005).
[10] A. Devilez, N. Bonod, J. Wenger, D. Gérard, B. Stout, H. Rigneault, and
E. Popov, “Three-dimensional subwavelength confinement of light with
dielectric microspheres” Opt. Express 17, 2089 (2009).
[11] I. Alessandri, N. Bontempi and L. E. Depero, “Colloidal lenses as
universal Raman scattering enhancers” RSC Advances 4, 38152 (2014).
[12] G. M. Das, R. Laha, and V. R. Dantham, “Photonic nanojet