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<p>Data acquisition and diagnostics for chemical and biological analytes are critical
to medicine, security, and the environment. Miniaturized and portable sensing systems
are especially important for medical and environmental diagnostics and monitoring
applications. Chip scale integrated planar photonic sensing systems that can combine
optical, electrical and fluidic functions are especially attractive to address sensing
applications, because of their high sensitivity, compactness, high surface specificity
after surface customization, and easy patterning for reagents. The purpose of this
dissertation research is to make progress toward a chip scale integrated sensing system
that realizes a high functionality optical system integration with a digital microfluidics
platform for medical diagnostics and environmental monitoring. </p><p>This thesis
describes the details of the design, fabrication, experimental measurement, and theoretical
modeling of chip scale optical sensing systems integrated with electrowetting-on-dielectric
digital microfluidic systems. Heterogeneous integration, a technology that integrates
multiple optical thin film semiconductor devices onto arbitrary host substrates, has
been utilized for this thesis. Three different integrated sensing systems were explored
and realized. First, an integrated optical sensor based upon the heterogeneous integration
of an InGaAs thin film photodetector with a digital microfluidic system was demonstrated.
This integrated sensing system detected the chemiluminescent signals generated by
a pyrogallol droplet solution mixed with H2O2 delivered by the digital microfluidic
system. </p><p>Second, polymer microresonator sensors were explored. Polymer microresonators
are useful components for chip scale integrated sensing because they can be integrated
in a planar format using standard semiconductor manufacturing technologies. Therefore,
as a second step, chip scale optical microdisk/ring sensors integrated with digital
microfluidic systems were fabricated and measured. . The response of the microdisk
and microring sensing systems to the change index of refraction, due to the glucose
solutions in different concentrations presented by the digital microfluidic to the
resonator surface, were measured to be 95 nm/RIU and 87nm/RIU, respectively. This
is a first step toward chip-scale, low power, fully portable integrated sensing systems.
</p><p>Third, a chip scale sensing system, which is composed of a planar integrated
optical microdisk resonator and a thin film InGaAs photodetector, integrated with
a digital microfluidic system, was fabricated and experimentally characterized. The
measured sensitivity of this sensing system was 69 nm/RIU. Estimates of the resonant
spectrum for the fabricated systems show good agreement with the theoretical calculations.
These three systems yielded results that have led to a better understanding of the
design and operation of chip scale optical sensing systems integrated with microfluidics.</p>
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