Nersisyan S.R.,BEAM Engineering for Advanced Measurements |
Tabiryan N.V.,BEAM Engineering for Advanced Measurements |
Mawet D.,European Southern Observatory |
Serabyn E.,Jet Propulsion Laboratory
Optics Express | Year: 2013
Vector vortex waveplates (VVWs) open the door to new techniques in stellar coronagraphy and optical communications, but the performance of currently available liquid-crystal-polymer-based VVWs tends to be limited by defects in the axial region of the vortex pattern. As described here, several steps allow for a reduction in the size of such axial defects, including the use of photoalignment materials with high photosensitivity and reversible response, and a reduction in exposure energy. Moreover, redistributing the writing beam's intensity from the axial region to its periphery (using a VVW) allows the production of large area VVWs with a small defect area. Finally, using VVWs as linear to axial polarization converters allows producing VVWs of higher topological charge, while also reducing the photoalignment time to a few minutes. These steps have allowed the fabrication of VVWs with topological charges of 1 and 2 with central defect sizes below 3 μm. © 2013 Optical Society of America.
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: 2016-06-22
Mirrors, lenses, devices, apparatus, systems and methods for correcting temporal dispersion of laser pulses or other pulses of electromagnetic radiation in diffractive telescopes used in applications, such as but not limited to optical telescopes, transmitters, receivers, and transceivers for laser communication and imaging. Diffractive lenses and mirrors allow for producing large area telescopes and reducing or eliminating temporal dispersion of laser pulses and other pulses of electromagnetic radiation recorded by such telescopes. This can be achieved by utilizing high efficiency thin film diffractive optical films, particularly, diffractive waveplates, and having a secondary diffractive mirror of a shape selected to assure that the propagation time from the flat primary collecting lens or mirror is independent of the position on the flat primary collecting lens or mirror at which the radiation impinges.
BEAM Engineering for Advanced Measurements | Date: 2014-02-28
Method for fabrication of vector vortex waveplates of improved quality due to reduced singularity size and widened spectral band, the method comprising creating a boundary condition for vortex orientation pattern of a liquid crystal polymer on a substrate using materials with reversible photoalignment, equalizing exposure energy over the area of the waveplate by redistributing the energy of radiation used for photoalignment from the center of the beam to its peripheries, and using vector vortex waveplate as a linear-to-axial polarization converter. Fabrication of spectrally broadband vector vortex waveplates further comprises two or more liquid crystal polymer layers with opposite sign of twist.
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
Agency: National Aeronautics and Space Administration | Branch: | Program: SBIR | Phase: Phase I | Award Amount: 99.99K | Year: 2011
Diffractive waveplates are optical components made of thin films of anisotropic materials by modulating their optical axis orientation in the plane of the waveplate. The family of diffractive waveplates wherein this modulation is axially symmetricÂ? vector vortex waveplates (VVWs) Â? impart a spiral phase modulation at a light beam propagated through the waveplate. As a result, the intensity of radiation is sharply decreased at the axis of the beam by many orders of magnitude, depending on the topological charge and quality of the VVW. Such transparent phase components can be successfully employed in coronagraphy allowing imaging of exoplanets at diffraction angle limit of their separation from the bright host star using small aperture telescopes, and they will allow increasing the imaging capability of large telescopes. To achievethis potential, VVWs shall possess with negligibly small singularity size (~ 2 micrometer) and be spectrally broadband in a large aperture (~ 25 mm). We propose to prove the feasibility of developing such components based on azobenzene photoalignment materials, liquid crystal polymers, and the optical printing technology that employs linear-to-axial polarization conversion. This feasibility will be proven in the Phase 1 by demonstrating achromatic VVWs in 700-900 nm spectral range and<10 micrometer singulary size.
Agency: National Aeronautics and Space Administration | Branch: | Program: SBIR | Phase: Phase II | Award Amount: 1.04M | Year: 2012
Using small aperture telescopes for detecting exoplanets could have a significant impact on astronomy and other imaging and space communication systems. In this new generation of smaller, lighter and more affordable coronagraph systems, the starlight is rejected with the aid of phase-based transparent masks capable of transmitting planetary light at small angular separation from the star. These so-called vector vortex waveplates (VVW) are complex optical components wherein the optical axis orientation is azimuthally modulated in space at a high spatial frequency. In the Phase 1 of the project, we showed the feasibility of fabricating VVWs that would meet requirements for astronomy applications due to small singularity size, high topological charge, high contrast, and broadband functionality. The breakthrough polarization conversion and beam shaping technology of printing VVWs developed in the Phase 1 will undergo further fundamental improvements in the Phase 2 of the project along with further optimization of photoalignment materials and liquid crystal polymers to fabricate and deliver VVWs characterized by: subwavelength singularity sizes; spectrally broadband/achromatic functionality, particularly, for infrared wavelengths; stability to radiation and large temperature variations; and functionality at cryogenic temperatures. This will accomplish the project's general objective development and delivery of VVWs adequate for practical use.
BEAM Engineering for Advanced Measurements | Date: 2014-03-02
Cycloidal boundary conditions for aligning liquid crystalline materials are obtained by mechanical rubbing of a polymer coating. The rubbing is performed by a rubbing head rotating around an axis perpendicular to the rubbing plane while the alignment polymer film is being translated across the rubbing film such as only a linear portion of the alignment film touches the rubbing film at any given time.
BEAM Engineering for Advanced Measurements | Date: 2015-04-16
Lenses, devices, apparatus, systems, methods of manufacturing and fabricating an ophthalmic lens device for correction of human vision. The ophthalmic lens device includes at least one diffractive waveplate coating with an optical axis orientation pattern designed to correct the vision of individual patients. The ophthalmic lens device including diffractive waveplate coating may also provide a portion of the required vision correction by means of refraction of light by curved surfaces of a dielectric material.