Silicon Nitride based Medium Contrast Gratings for Doubly Resonant Fluorescence Enhancement
We present the design, fabrication, and experimental characterization of silicon nitride based medium-index contrast gratings on glass substrate for fluorescence enhancement in the yellow to red spectral range with resonances for both incident excitation and fluorescence emission wavelengths under s...
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IEEE
2019-01-01
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| Series: | IEEE Photonics Journal |
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| Online Access: | https://ieeexplore.ieee.org/document/8684253/ |
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| author | Sruti Hemachandran Geetha Menon A. S. Lal Krishna Varun Raghunathan |
| author_facet | Sruti Hemachandran Geetha Menon A. S. Lal Krishna Varun Raghunathan |
| author_sort | Sruti Hemachandran Geetha Menon |
| collection | DOAJ |
| description | We present the design, fabrication, and experimental characterization of silicon nitride based medium-index contrast gratings on glass substrate for fluorescence enhancement in the yellow to red spectral range with resonances for both incident excitation and fluorescence emission wavelengths under surface normal incidence. A comparison of the design space to realize resonant field enhancement in high-index contrast silicon and medium-index contrast silicon nitride grating structures is presented. The one-dimensional sub-wavelength grating structures studied here are designed with large duty cycle (∼80%) to account for the medium refractive index contrast (Δn ∼ 0.5) between silicon nitride and the glass substrate to ensure that the device operates in the two-mode regime. The resonant enhancement of fluorescence is experimentally verified using rhodamine-B isothiocyanate dye as the fluorophore of interest. A resonant enhancement of 10.8 times is demonstrated in this sample when compared to un-patterned film for transverse electric-transverse magnetic (TE–TM) polarization combination. We have also performed simulation study with plane wave excitation and incoherent dipole array emission to model the resonant excitation and emission processes, respectively. The simulations corroborate well with the best observed experimental results for the doubly resonant fluorescence configuration. Silicon nitride based medium contrast gratings are a promising platform to fabricate scalable structures for resonant enhancement of light–matter interaction with potential applications in high-sensitivity biological fluorescence assays and as a platform for polarization selective interrogation of light emission from nanoscale emitters attached to the grating. |
| format | Article |
| id | doaj-art-2f8a2cd4ffdb4e519e102c81b96bee95 |
| institution | Kabale University |
| issn | 1943-0655 |
| language | English |
| publishDate | 2019-01-01 |
| publisher | IEEE |
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| series | IEEE Photonics Journal |
| spelling | doaj-art-2f8a2cd4ffdb4e519e102c81b96bee952025-08-20T03:32:33ZengIEEEIEEE Photonics Journal1943-06552019-01-0111411110.1109/JPHOT.2019.29097948684253Silicon Nitride based Medium Contrast Gratings for Doubly Resonant Fluorescence EnhancementSruti Hemachandran Geetha Menon0A. S. Lal Krishna1Varun Raghunathan2https://orcid.org/0000-0002-0141-4032Department of Electrical and Communication Engineering, Indian Institute of Science, Bengaluru, IndiaDepartment of Electrical and Communication Engineering, Indian Institute of Science, Bengaluru, IndiaDepartment of Electrical and Communication Engineering, Indian Institute of Science, Bengaluru, IndiaWe present the design, fabrication, and experimental characterization of silicon nitride based medium-index contrast gratings on glass substrate for fluorescence enhancement in the yellow to red spectral range with resonances for both incident excitation and fluorescence emission wavelengths under surface normal incidence. A comparison of the design space to realize resonant field enhancement in high-index contrast silicon and medium-index contrast silicon nitride grating structures is presented. The one-dimensional sub-wavelength grating structures studied here are designed with large duty cycle (∼80%) to account for the medium refractive index contrast (Δn ∼ 0.5) between silicon nitride and the glass substrate to ensure that the device operates in the two-mode regime. The resonant enhancement of fluorescence is experimentally verified using rhodamine-B isothiocyanate dye as the fluorophore of interest. A resonant enhancement of 10.8 times is demonstrated in this sample when compared to un-patterned film for transverse electric-transverse magnetic (TE–TM) polarization combination. We have also performed simulation study with plane wave excitation and incoherent dipole array emission to model the resonant excitation and emission processes, respectively. The simulations corroborate well with the best observed experimental results for the doubly resonant fluorescence configuration. Silicon nitride based medium contrast gratings are a promising platform to fabricate scalable structures for resonant enhancement of light–matter interaction with potential applications in high-sensitivity biological fluorescence assays and as a platform for polarization selective interrogation of light emission from nanoscale emitters attached to the grating.https://ieeexplore.ieee.org/document/8684253/Subwavelength gratingsguided-mode resonancefluorescenceoptical resonance. |
| spellingShingle | Sruti Hemachandran Geetha Menon A. S. Lal Krishna Varun Raghunathan Silicon Nitride based Medium Contrast Gratings for Doubly Resonant Fluorescence Enhancement IEEE Photonics Journal Subwavelength gratings guided-mode resonance fluorescence optical resonance. |
| title | Silicon Nitride based Medium Contrast Gratings for Doubly Resonant Fluorescence Enhancement |
| title_full | Silicon Nitride based Medium Contrast Gratings for Doubly Resonant Fluorescence Enhancement |
| title_fullStr | Silicon Nitride based Medium Contrast Gratings for Doubly Resonant Fluorescence Enhancement |
| title_full_unstemmed | Silicon Nitride based Medium Contrast Gratings for Doubly Resonant Fluorescence Enhancement |
| title_short | Silicon Nitride based Medium Contrast Gratings for Doubly Resonant Fluorescence Enhancement |
| title_sort | silicon nitride based medium contrast gratings for doubly resonant fluorescence enhancement |
| topic | Subwavelength gratings guided-mode resonance fluorescence optical resonance. |
| url | https://ieeexplore.ieee.org/document/8684253/ |
| work_keys_str_mv | AT srutihemachandrangeethamenon siliconnitridebasedmediumcontrastgratingsfordoublyresonantfluorescenceenhancement AT aslalkrishna siliconnitridebasedmediumcontrastgratingsfordoublyresonantfluorescenceenhancement AT varunraghunathan siliconnitridebasedmediumcontrastgratingsfordoublyresonantfluorescenceenhancement |