Share Email Print
cover

Proceedings Paper • new

Silicon-nitride-based medium-contrast gratings for resonant fluorescence enhancement in the visible wavelength range
Format Member Price Non-Member Price
PDF $14.40 $18.00
cover GOOD NEWS! Your organization subscribes to the SPIE Digital Library. You may be able to download this paper for free. Check Access

Paper Abstract

In this work, we have designed, fabricated and characterized silicon nitride sub-wavelength gratings on glass substrate to enhance the fluorescence in the green-red wavelength range. Silicon nitride was chosen as the material to fabricate the gratings as it exhibits low absorption losses and negligible fluorescence at visible wavelengths. Due to lower refractive index contrast, the structures were designed such that the medium index contrast gratings still achieve good quality factor resonances by using higher duty cycles (~ 70%) which clearly distinguishes two-mode region from higher order diffraction regime. The designed structure (Duty cycle: ~70%, thickness: 290nm, pitch: 370nm) supports resonant modes at 542nm for TE and at 548nm and 568nm for TM polarization. Rhodamine B dye was attached to the grating through an intermediate polymer layer PAH (Polyallylamine hydrochloride) by dip coating method. Using a fluorescence microscope with suitable excitation (510-550nm) and emission (>590nm) filters, we observed fluorescence enhancement of 5.4x and 5.8x in TE and TM modes respectively.

Paper Details

Date Published: 4 March 2019
PDF: 6 pages
Proc. SPIE 10928, High Contrast Metastructures VIII, 1092818 (4 March 2019); doi: 10.1117/12.2508778
Show Author Affiliations
Sruti Menon, Indian Institute of Science (India)
Lal Krishna A. S., Indian Institute of Science (India)
M. V. N. Surendra Gupta, CSIR-Central Electronics Engineering Research Institute (India)
Academy of Scientific and Innovative Research (India)
Ameen E., CSIR-Central Electronics Engineering Research Institute (India)
Academy of Scientific and Innovative Research (India)
Bala Pesala, CSIR-Central Electronics Engineering Research Institute (India)
Academy of Scientific and Innovative Research (India)
Varun Raghunathan, Indian Institute of Science (India)


Published in SPIE Proceedings Vol. 10928:
High Contrast Metastructures VIII
Connie J. Chang-Hasnain; Andrei Faraon; Weimin Zhou, Editor(s)

© SPIE. Terms of Use
Back to Top