Download Bio Nano Photonic Scientific and Technical Objectives

Bio Nano Photonic
Scientific and Technical Objectives
Photonics
technology
has
become
an
important
part
of
our
daily
life,
spanning
telecommunications, displays, lighting, renewable energy to biomedical sensors and devices.
Particularly, the current worldwide introduction of Fibre-to-the-Home technologies necessitates
components which are efficient, cheap, easy to install and environmentally safe. Most active
devices rely on inorganic semiconducting compounds. The increasing use of nanostructures has
created a concomitant increase in complexity and cost of fabrication equipment. Furthermore,
the chemicals used in most active devices, e.g. GaInAlAs or InP, contain heavy metals and toxic
halides. In this proposal, a novel interdisciplinary approach to deal with all the above issues by
microbiological fabrication of photonic nanocomposites is taken, which has the additional
benefit of addressing lifecycle issues.
This proposal is a model project to demonstrate and develop the convergence of sciences,
spanning the entire range from fundamental cutting-edge nanoscience to generic bio-based
composite material development to ultrafast and nonlinear optics, leading ultimately to photonics
applications.
Fundamental scientific and technological questions
1. Microbiological synthesis and extraction of highly complex, but exceptionally
well defined inorganic nanostructures.
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fundamental
scientific
interest
but also technological relevance,
e.g. Se nanospheres and Te
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nanorods, As-S nanotubes, CdSe
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and ZnSe quantum dots. This biolact
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complicated
synthetically.
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complex
structures which are too difficult
or
b
and
enables
to
produce
2. The precise control of physical and electronic structure in such nanoparticles
enables the development of fundamental structure-property relationships of
complex nanostructures
This, in turn, results in exceptional optical properties:
 Absorption and emission properties are controlled by the nanostructure and
particularly tuneable across all the important photonic wavelength range in the near
infrared, i.e. from 0.7 – 1.8 micron.
 The nonlinear and photoemission properties are enhanced substantially compared to
similar chemically synthesised nanomaterials by increased density of states due to
complex constructive interplay of dielectric and quantum confinement.
 The excited state relaxation processes are generally in the ultrafast ps-fs range due to
structural confinement of the nanoscale – thus enabling applications in ultra-high
speed switching and controlling of light.
3. ‘Green’ Polymer Photonic Nanocomposites
As such nanostructures can be incorporated into a similarly microbiologically fabricated
transparent polymer host matrix, i.e. biodegradable Polyhydroxyalkanoate by either solution or
melt processing, practical nanocomposites can be made relatively simply. This new class of ‘upcycled, green’ materials represents a novel and promising approach to deal with the problems
of raw material cost and continuity of supply, toxicity and recycling, with the additional benefit of
addressing lifecycle issues and thus contributing to the preservation of our environment through
reuse of heavy metal waste. In addition, these polymer nanocomposites will provide an ideal
platform for new photonic technologies: Standard optical devices are based on guided-wave
technology and use mainly traditional semiconductor and glass technology. However this has hit
a limit given mainly by economic but also materials and fabrication restrictions.
Technology
Devices
Coupling to SMF
and PLC*
Fabrication
Silica-based
Complex; Passive (e.g.
arrayed routers)
Well-Matched
Few Steps
Semiconductorbased
Compact; Active (e.g.
optical amplifiers, lasers,
fast modulators, and
detectors)
Difficult due to tightly
confined waveguide
modes
Complex Epitaxial
Processing and Multiple
Step Photolithography
* SMF = Single mode fibres; PLC = planar light wave circuits
Hence, it is desirable to construct optical devices that share the favourable attributes of each
technology; i.e. mode matched to SMF, simple processing, and the capability of providing an
electro-optic effect, optical gain, and/or absorption. Bio-based nanoparticle doped polymer
waveguides will solve this problem.
4. The fundamental study on the ultrafast and nonlinear optical properties of
nanomaterials is a critical link to real-life applications
The backbone of photonic and information technologies is composed of photonic devices which
modify optical signals by amplification, transmittance, modulation and transformation processes.
A high performance photonic device requires a fast response time, strong nonlinearity, a broad
wavelength range, low cost and ease of integration into an optical system. So far, a few materials,
such as carbon nanotubes and Au and Ag nanoparticles have partially fulfilled the above
requirements. Here we will explore the ultrafast nonlinear properties of microbiologically
synthesised nanomaterials to demonstrate their usefulness in selected of nanophotonic devices,
such as optical switches, saturable absorbers, mode-lockers, optical limiters and possibly also solar
cells.