The proof of concept for a photonic cavity sensor for oil, water and gas detection is reported. The optical design employs an optimized photonic crystal cavity with fluidic infiltration of gas, water or (reservoir) oils. The 3D design and simulation is discussed, followed by the nanofabrication in standard silicon on insulator wafers (SoI). Using an optofluidic cicuit with PDMS channels, the fluid flow to the photonic cavity is controlled with syringe pumps. The variations in dielectric value (refractive index) change with the involved media result in a shift of the cavity resonant wavelength. For fluid change from water to typical oil (refractive index difference of 0.12), we report a wavelenght shift of up to 12 nm at the measurement wavelength of 1550 nm, in very good agreement with the simulations. We follow the optical response at a fixed wavelength, when feeding alternate flows or bubbles of oil/water through the optofluidic chip, and observe the flow pattern on camera. Finally we discuss the outlook and antifouling of the sensor with a special design. This work is supported by Shell Global Solutions.
Appl.Phys.Lett., 106, 031116 (2015)
J.Lightw.Technol., 33, 3672 (2015)
A design of a point-defect cavity in two-dimensional photonic crystal slab with both high Q factor and high transmission
intensity has been achieved by adjusting the radii and position of lattice points in both parallel and perpendicular
directions. Analysis shows that discrete resonant modes have been found in the 1550 wavelength range with Q factors up
to 40,000. Moreover, the cavity was verified to subject to minor intensity decrease of 1.2 dB due to the introducing of
external waveguide access. All these features make the cavity a very promising candidate for light transmission and
detection in practical application. We also demonstrate the potential application of such a cavity being used as a sensitive
index sensor with a high sensitivity of 400nm/refractive index unit.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.