Piezoceramic actuators are of increasing interest within the field of adaptive optics through their ability for macro and
nano positioning. However, a major drawback for their use is the inherent, non linear hysteresis that is present, which
will reduce the accuracy in positioning. Typical (raw) hysteresis for multilayered piezoceramic actuators is 20% of full
extension. Methods have been researched to overcome the hysteresis but they often involve complex additions to the
actuators and its positioning system. This paper discusses two methods to overcome the hysteresis in a simpler approach.
The first method is using capacitance measurements which correlate with the extension of the actuators and reduces
hysteresis to 5%. The second method involves measuring the frequency at a specific impedance phase, which can reduce
hysteresis to between 0 - 2%. Both methods provide reduction in hysteresis during extension sensing.
The development of air-tight buildings to significantly reduce the carbon emissions from buildings is a relatively new
building technique. However the side effects of the new approach have not been fully investigated. One potential issue
arising is from insufficient ventilation resulting in an increase in poor indoor air quality from exacerbated microbial
growth through elevated humidity and temperature. At the moment there is no in situ real-time sensor for the detection
of multiple microbes within the built environment.
Developing a sensor utilizing the phenomena of Surface Plasmon Resonance as its detection method to continuously
monitor in situ multiple microbial species and fungi is being undertaken. The research involves the refinement of the
specialised instruments commercially available, simplifying the components and advancing the architecture of the
interface allowing for the monitoring of multiple species and a novel output detection method.
Plasmonics is an area of nanophotonic research involving the interactions of electromagnetic radiation and conduction
electrons on a metallic surface, resulting in enhanced optical properties. Plasmonics is the mechanism behind Surface
Plasmon Resonance (SPR.) Developing a sensor using SPR to monitor conditions within the built and natural
environment is explored in this paper.
A plasmonic sensor involves exciting surface plasmon polaritons (SPP's) present at the sensor interface by polarized
light. SPP's have sensitivities that respond rapidly to changes at the interface through the presence of analytes,
compounds or contaminants; this provides a real time label free detection method. This renders plasmonic sensors ideal
as condition monitors. Possible applications include, microbial loading within airtight buildings, soil, water and air
pollutant monitoring and structural deterioration monitoring. The advances and learning curves in the development of a
new novel sensor for deployment within the built and natural environment are presented along with initial research
findings.
Within the Built and Natural Environment early analysis of structural conditions, air quality monitoring,
pollutant and irritant detection by optical sensor technology is advancing. Combining the two technologies,
Surface Plasmon Resonance (SPR) and Surface Enhance Raman Scattering (SERS) into a single instrument
is the aim of the research, with a resulting fingerprint library of measurands being produced.
The combo sensor will provide unique fingerprints of the measurands, monitoring conditions, such as the
carbonation of concrete, microbial and chemical loading and ageing effects of structures, along with their
severity. Analysed conditions will be crossed referenced with the library allowing smart feedback for timely
maintenance.
SPR and SERS work on the principle that specific surfaces, when excited by a light source passing through a
glass prism, will change their rate and scale of vibration when their surface holds or is contaminated by
particular a component, in this case the monitoring condition analyte. A ligand, which binds specifically to
the monitoring analyte, is held in specialised surface coatings which are applied to the surface of the sensor
glass or prism itself. The sensing takes place through detection of differences in the original laser light
source and reflections/refractions of that light source from the glass prisms.
The advances and obstacles of early research are discussed along with initial results and findings being
examined in the development a new optical combo sensor.
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.