Masters Theses


Raghu Ambekar


"Optical oxygen sensors are the most popular type of oxygen sensors because of their advantageous features like fast response, no electrical interference, high sensitivity and no oxygen consumption compared to its electrochemical counterpart. Most of the optical oxygen sensors are based on the principle that oxygen quenches the luminescence emitted from the luminescent dyes, such as porphyrin and ruthenium complex, which are immobilized in an oxygen permeable membrane. In bio-MEMS applications, there is a large need of microscopically patterned optical membranes to measure chemical parameters in a small local area. Most of the oxygen sensitive membranes are. however, non-patternable and very little progress has been made towards producing patternable optical membranes. In this work, a new class of optical oxygen sensors that can be photopatternable by traditional UV lithography is presented. They are fabricated using photopatternable spin-on silicone (polydimethylsiloxane, PDMS) with oxygen sensitive luminescent dyes. It has good adhesion properties and can be applied on glass and on photopolymer (SU-8) without any additional surface treatments. The optimum mixture composition for patternable oxygen sensitive membranes is investigated. Its optical properties are characterized and two applications, intensity-based oxygen sensing with SU-8 vertical optical waveguides and self-calibration microfluidic oxygen sensor, are successfully demonstrated. These photopatternable optical membranes will find many applications wherever small patterns of oxygen sensitive membranes are required in both intensity-based and lifetime-based optical sensors"--Abstract, page iv.


Kim, Chang-Soo

Committee Member(s)

Watkins, Steve Eugene, 1960-
Henthorn, David


Electrical and Computer Engineering

Degree Name

M.S. in Electrical Engineering


This research was supported by NSF (ECS-0644679).


Missouri University of Science and Technology

Publication Date

Spring 2008

Journal article titles appearing in thesis/dissertation

  • Process development for waveguide chemical sensors with integrated polymeric sensitive layers
  • Patternable polymeric membranes for optical oxygen sensors


viii, 40 pages

Note about bibliography

Includes bibliographical references.


© 2008 Raghu Ambekar Ramachandra Rao, All rights reserved.

Document Type

Thesis - Restricted Access

File Type




Subject Headings

Chemical detectors
Membranes (Technology)
Optical detectors
Optical wave guides

Thesis Number

T 9375

Print OCLC #


Link to Catalog Record

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