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Lee K.M.,Air Force Research Lab | Lee K.M.,Azimuth Corporation | Tabiryan N.V.,BEAM Engineering for Advanced Measurements | Bunning T.J.,Air Force Research Lab | White T.J.,Air Force Research Lab
Journal of Materials Chemistry | Year: 2012

Azobenzene-functionalized polymeric materials have proven capable of shape adaptive responses when irradiated with light. This work focuses on isolating the fundamental differences between the photogenerated mechanical output of glassy, polydomain azobenzene liquid crystal polymer networks (azo-LCN) upon exposure to either UV and blue-green irradiation. Profound differences in the fundamental photochemical mechanism are identified through spectroscopic examination of representative materials before and after irradiation with UV or blue-green light. The photomechanical response is further elucidated in structure-property examination to ascertain the role of crosslink density, azobenzene concentration, and azobenzene connectivity (crosslinked or pendant) on the photomechanical output. © 2012 The Royal Society of Chemistry. Source

Piccardi A.,Nonlinear Optics and OptoElectronics Laboratory NooEL | Alberucci A.,Nonlinear Optics and OptoElectronics Laboratory NooEL | Tabiryan N.,BEAM Engineering for Advanced Measurements | Assanto G.,Nonlinear Optics and OptoElectronics Laboratory NooEL
Optics Letters | Year: 2011

We experimentally demonstrate and model dark spatial solitons in azo-doped liquid crystals, in the presence of saturation and nonlocality of the effective nonlinearity due to changes in molecular order. The guiding properties of dark solitons are probed with a weak input of different wavelength. © 2011 Optical Society of America. Source

BEAM Engineering for Advanced Measurements | Date: 2010-01-29

The objective of the present invention is providing optical systems for controlling with propagation of light beams in lateral and angular space, and through optical apertures. Said light beams include laser beams as well as beams with wide spectrum of wavelengths and large divergence angles. Said optical systems are based on combination of diffractive waveplates with diffractive properties that can be controlled with the aid of external stimuli such as electrical fields, temperature, optical beams and mechanical means.

BEAM Engineering for Advanced Measurements | Date: 2010-04-21

The objective of the present invention is providing a method for fabricating high quality diffractive waveplates and their arrays that exhibit high diffraction efficiency over large area, the method being capable of inexpensive large volume production. The method uses a polarization converter for converting the polarization of generally non-monochromatic and partially coherent input light beam into a pattern of periodic spatial modulation at the output of said polarization converter. A substrate carrying a photoalignment layer is exposed to said polarization modulation pattern and is coated subsequently with a liquid crystalline material. The high quality diffractive waveplates of the present invention are obtained when the exposure time of said photoalignment layer exceeds by generally an order of magnitude the time period that would be sufficient for producing homogeneous orientation of liquid crystalline materials brought in contact with said photoalignment layer. Compared to holographic techniques, the method is robust with respect to mechanical noises, ambient conditions, and allows inexpensive production via printing while also allowing to double the spatial frequency of optical axis modulation of diffractive waveplates.

Agency: National Aeronautics and Space Administration | Branch: | Program: SBIR | Phase: Phase I | Award Amount: 124.53K | Year: 2014

In future ground-based receivers for deep-space optical communications with spacecraft, aperture diameters of the order of 10 meters are required even with the most sensitive available detectors. Directly applying the technology of 10 meter class ground-based telescopes is cost prohibitive. Also, conventional astronomical telescopes are not compatible with operation within 5 degees of the sun, but such near-sun operation is required with the Ground-based Telescope Assembly to provide consistent and reliable wideband communications with interplanetary spacecraft. BEAM Co. proposes to develop a telescope based on diffractive optics that is expected to be far less expensive to manufacture than a telescope based on conventional reflective optics. Our approach takes advantage of the well-defined wavelength of the optical communications beam, thus allowing a high-efficiency design that is expected to be much lighter than a conventional design, thereby reducing the cost of the system that will be used to point the telescope. At the end of Phase I, we will have fabricated and tested subscale diffractive optical elements and performed tests to validate the technology's scalability to large apertures and its capability to support the

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