Photonics

Cleaning and Protecting Large Mirrors Using a Polymer Solution

Cleaning and protecting optics is a challenge — contamination must be removed without damaging the surface. Preventing recontamination for extended periods of time after cleaning was unattainable prior to use of polymer strip coat films. The SLRSC Western Range Depot Optics Group, WRDOG, at Vandenberg Air Force Base, is a pioneer in the cleaning and protection of precision glass optics, lenses, and large mirrors using polymer solution technology.

Posted in: Briefs, Photonics, Mirrors, Coatings Colorants and Finishes, Polymers
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Advances in Materials for Photonic Applications

Air Force Research Laboratory, Wright-Patterson Air Force Base, Ohio Aprogram of research has addressed multiple topics in the design, development, characterization, and utilization of new materials for photonic applications. These materials include compounds, solutions, and nanocomposites that exhibit diverse types of single- and multiple-photon activity. The accomplishments of this research can be grouped into four main categories and summarized as follows:

Posted in: Briefs, Photonics
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Compact Megawatt Infrared Free-Electron Laser Amplifier

A proposed high-gain free-electron laser (FEL) amplifier, conceived primarily for use in a maritime environment, would be capable of average output power of the order of a megawatt at one or more of several infrared wavelengths (1.045, 1.625, or 2.141 μm) for which propagation through air is minimally adversely affected by water vapor and aerosols. The conceptual design of this FEL amplifier provides for a combination of conventional and unconventional characteristics that, taken together, would be advantageous in the intended power and wavelength regime.

Posted in: Briefs, Photonics
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Apparatus Generates CE-Phase-Stable Two-Cycle Optical Pulses

A n apparatus that includes two optical parametric chirped pulse amplification stages has been built as a means of generating few-cycle, common-envelope (CE)-phase-stable, high-energy optical pulses. [CE phase is the phase of an optical carrier-signal waveform relative to the pulse envelope waveform. CE phase is an important property of fewcycle pulses, and CE-phase stability is essential in typical applications involving few-cycle pulses.] The apparatus can generate two-cycle (14-fs-duration) pulses at a nominal middle wavelength of 2 μm, and two-cycle (5-fs-duration) pulses at a nominal middle wavelength of 800 nm at a repetition rate of 1 kHz, without need for pulse compression by an external apparatus. The apparatus is intended for use in high-harmonic generation (HHG) of extreme ultraviolet (EUV) and soft x-rays in the near term, extending to production of attosecond EUV and soft-x-ray pulses in the longer term. Moreover, this apparatus is expected to enable exploration of generation of fewand single-cycle laser pulses over the wavelength range from 700 to 2.6 μm.

Posted in: Briefs, Photonics
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Terahertz Fiber-Optic Lasers for Detection of Explosives

Fiber-optic lasers of a proposed type would serve as sources of coherent radiation at frequencies between 0.5 and 4.0 THz and output power levels ≥100 mW. In the original application envisioned in the proposal, these lasers would be parts of compact, man-portable instruments for detection of explosives.

Posted in: Briefs, Photonics
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Research on Quantum Communication Repeaters

A program of research during the years 2001 through 2006 was devoted to building theoretical and practical foundations for the development of quantum repeaters as means of overcoming losses of photons in long-distance quantum communication systems. The idea underlying this research was to investigate means of utilizing suitably prepared ensembles of atoms (e.g. rubidium vapors) as means of storing and transferring the information encoded in the states of photons. The main accomplishments of this research, in approximate chronological order, include the following:

Posted in: Briefs, Photonics
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Optical-Fiber Infrasound Sensors

Optical-fiber infrasound sensors (OFISs) are being developed for detecting acoustic pressures in the frequency range from a few millihertz to a few hertz. As explained below, these sensors were conceived to overcome some of the limitations of prior infrasound sensors based on pipe filters connected to microbarographs.

Posted in: Briefs, Photonics, Fiber optics, Sensors and actuators, Acoustics
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Study of Membrane Optics for Lightweight Space Telescopes

Astudy has been performed to establish a foundation for the analysis, design, and further development of inplane- actuated deformable membrane mirrors for lightweight spaceborne telescopes. It is envisioned that the telescopes, having typical mirror diameters of 20 m or larger, would be stowed compactly for launch and transport, then deployed in orbit around the Earth for use in surveillance of the Earth and in exploration of deep space.

Posted in: Briefs, Photonics, Mirrors, Optics, Test equipment and instrumentation
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Miniature Hyperspectral Sensors for Imaging on Small UAVs

As unmanned vehicles get smaller and smaller, operational expectations and mission objectives demand a much broader array of platform capabilities — a necessity even with reduced payloads requiring less weight, smaller size, and less power consumption. An interesting dichotomy exists between the need for increasing amounts of valuable information and the operational ability to capture and synthesize this information in real time.

Posted in: Briefs, Photonics, Imaging, Sensors and actuators, Unmanned aerial vehicles
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Photonic Analog-to-Digital Converters

Early steps have been taken toward the development of analog-to-digital converters (ADCs) that would incorporate photonic quantizers based on the technology of InP semiconductors. These photonic ADCs are intended to overcome the sampling speed and temporal resolution limitations of state-ofthe- art all-electronic ADCs, so that outputs of radar and other sensor systems at frequencies as high as tens of gigahertz could be sampled directly, without need for analog signal processing to effect down-conversion in frequency prior to sampling.

Posted in: Briefs, Photonics, Electronic equipment, Radar, Sensors and actuators, Semiconductors
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