Transcript ppt - University of Cambridge

H.J. Coles, T.D. Wilkinson
11 Post-Doctoral Research Associates, 13 PhD Research Students
Research at CMMPE
Liquid crystal lasers
CMMPE was officially opened in 2003 by Lord
Sainsbury of Turville. It is an 'embedded'
research centre in the Centre for Advanced
Photonics and Electronics (CAPE). Based in
the Electrical Engineering Division on the West
Cambridge Site, it is one of three parallel
photonics research groups.
CMMPE combines research scientists from a
number of different disciplines including organic
chemistry, physics and engineering. This enables
fundamental research to be carried out in the
design and synthesis of organic materials for the
next generation of photonic and electronic
applications. Our research areas include:
• Liquid crystal lasers
• Liquid crystals for telecoms
• 2D & 3D holographic projection
• Optical pattern recognition
• Liquid crystals for displays
• Flexoelectro-optic effect
• Electrical & optical
characterisation of dielectrics
Chiral nematic liquid crystals have been
shown to display a photonic band-gap and a
periodic structure. From this, new varieties of
micromolecular organic lasers are being
developed, with the following properties:
- Micrometer dimensions
- Tunable emission wavelength
- Single mode
- High output power
- Large coherence area
- Low threshold
- Self-organising into periodic structures
CMMPE is developing new LC laser
structures, such as arrays of recombinable laser sources (above right),
improving their performance, and using
this technology to develop new
applications.
• Hybrid liquid crystal carbon
nanotube devices
• Adaptive optics for ophthalmic
imaging
• Non-linear optics
Adaptive phase modulation devices
CMMPE is developing new adaptive devices that
CMMPE is developing new adaptive devices that
dynamically manipulate of the phase of light,
dynamically manipulate of the phase of light,
often using liquid crystals.
Examples and
often using liquid crystals.
Examples and
applications of such devices include:
applications of such devices include:
- 2D & 3D computer generated holography
- 2D & 3D computer generated holography
Left - a computer generated hologram is used to
(left - a computer generated hologram is used to
display a video of a clock face.
display a video of a clock face).
- Adaptive optics for ophthalmic imaging
- Adaptive optics for ophthalmic imaging
- Optical pattern recognition (comparators)
- Optical pattern recognition (comparators)
Liquid crystals for displays
Our research themes in the field of flat-panel liquid crystal displays
encompass a range of different electro-optic effects that are suitable for
applications including fast-switching, video frame-rate liquid crystal displays,
and large area, low-power consumption, displays. The work programs can be
categorised into the following headings:
- Blue phases
- Flexoelectro-optic effect
- Ferroelectrics
- Antiferroelectrics
- Smectic A
- PDLCs
- Hybrid devices
- Dye guest-host systems
Hybridliquid
liquid crystal carbon
- -Hybrid
carbon nanotube
nanotube
devices
(rightdevices
– a sparse array of vertically
aligned
nanotubes
are grownaligned
on a
Right –carbon
a sparse
array of vertically
substrate
and
used
to
electrically
address
a
carbon nanotubes are grown on a substrate
nematic
liquid
crystal, generating
and used
to electrically
address aaGaussian
nematic
electric
field,
and
a
switchable
optical
device,
liquid crystal, generating a Gaussian electric
similar
an adaptive
microlens
array).device,
field, toand
a switchable
optical
Above – (a) Chiral nematic structure, (b)
deformation due to flexoelectro-optic and
(c) dielectric coupling to an E field
orthogonal to the helical axis.
Left – Liquid crystal blue phases are selfassembled 3D cubic defect structures, with
lattice periods of the order of the
wavelength of visible light.
similar to an adaptive microlens array.
www-g.eng.cam.ac.uk/CMMPE