Resonant Mode Engineering of Photonic Crystal Sensors Clad with Ultralow Refractive Index Porous Silicon Dioxide
- Univ. of Illinois at Urbana-Champaign, IL (United States). Dept. of Electrical and Computer Engineering; Beihang Univ., Beijing (China). School of Electronic and Information Engineering
- Univ. of Illinois at Urbana-Champaign, IL (United States). Dept. of Materials Science and Engineering
- Univ. of Illinois at Urbana-Champaign, IL (United States). Dept. of Electrical and Computer Engineering, Micro and Nanotechnology Lab.
- Univ. of Illinois at Urbana-Champaign, IL (United States). Dept. of Electrical and Computer Engineering, Micro and Nanotechnology Lab., and Dept. of Bioengineering
Abstract Porous SiO 2 (PSiO 2 ) with ultralow refractive index ( n = 1.09) is incorporated as the cladding of a photonic crystal (PC) refractive index sensor with enhanced sensitivity through the establishment of resonant modes that principally reside in the liquid medium covering the PC surface. PSiO 2 , obtained by thermal oxidation of porous Si that has been transferred to a transparent substrate, is transparent at visible and near infrared wavelengths with a refractive index determined by its porosity. The PSiO 2 periodic grating structure (Λ = 590 nm) is patterned by nanoimprint lithography and reactive ion etching, then conformally coated by sputtering high refractive index TiO 2 to seal the pores from liquid infiltration. With the refractive index of PSiO 2 much lower than that of water, the resonant mode “flips” its spatial distribution from within the solid dielectric regions of the photonic crystal to reside mainly in the water media covering the PC, resulting in 4× greater resonant wavelength shift for a fixed refractive index change. This study demonstrates design, fabrication, and testing of the sensor as a refractometer, supported by electromagnetic simulations of the resonant mode spatial distribution, in which porous PC sensors are compared to nonporous PC sensors.
- Research Organization:
- Energy Frontier Research Centers (EFRC) (United States). Light-Material Interactions in Energy Conversion (LMI)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES)
- Grant/Contract Number:
- SC0001293; DE‐SC0001293
- OSTI ID:
- 1470416
- Alternate ID(s):
- OSTI ID: 1378114
- Journal Information:
- Advanced Optical Materials, Vol. 5, Issue 21; Related Information: LMI partners with California Institute of Technology (lead); Harvard University; University of Illinois, Urbana-Champaign; Lawrence Berkeley National Laboratory; ISSN 2195-1071
- Publisher:
- WileyCopyright Statement
- Country of Publication:
- United States
- Language:
- English
Web of Science
Similar Records
Tunable Visibly Transparent Optics Derived from Porous Silicon
Optically anisotropic porous silicon microlenses with tunable refractive indexes and birefringence profiles
Related Subjects
36 MATERIALS SCIENCE
42 ENGINEERING
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
solar (photovoltaic)
solid state lighting
phonons
thermal conductivity
electrodes - solar
materials and chemistry by design
optics
synthesis (novel materials)
synthesis (self-assembly)