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Results for “OPTICAL FILTER”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 19 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1996

Efficient, Narrow-Pass-Band Optical Filters

Optical filters with both narrow pass bands and high efficiencies fabricated to design specifications. Offer tremendous improvements in performance for number of optical (including infrared) systems. In fiber-optic and free-space communication systems, precise frequency discrimination afforded by narrow pass bands of filters provide higher channel capacities. In active and passive remote sensors like lidar and gas-filter-correlation radiometers, increased efficiencies afforded by filters enhance detection of small signals against large background noise. In addition, sizes, weights, and power requirements of many optical and infrared systems reduced by taking advantage of gains in signal-to-noise ratios delivered by filters.

Sandford, Stephen P.↗
NASA NTRS1992

Effects of space exposure on optical filters

Optical transmittance characteristics of nine optical filters were remeasured after nearly six years in space aboard the NASA Long-Duration Exposure Facility. Three different filter types were included. In general, transmittance decreased for most filters. The center frequency and bandpass of a narrow-band filter under an aluminum cover were unchanged, while narrow-band filters exposed directly to the space environment tended to show a shift in center frequency and increased bandwidth. A pair of infrared-reflecting mirrors exhibited reduced transmittance in the visible, with a mirror under an aluminum cover less degraded than a mirror exposed to space. The bandpass was unchanged for both of these mirrors. Neutral density filters showed a slight increase in transmittance for an uncovered filter; essentially no change for the filter under the aluminum cover.

Blue, M. D.↗
NASA NTRS1977

Electrically-controlled variable-color optical filters

Optical transmission characteristics of birefringent element are changed by applying voltage to plate. Filters are used on sequential-color television cameras and in color displays. Filters are more convenient and less costly than mechanical color wheels and crystal-based filters.

Miller, A.↗
NASA NTRS2013

Optical Filter Assembly for Interplanetary Optical Communications

Ground-based, narrow-band, high throughput optical filters are required for optical links from deep space. We report on the development of a tunable filter assembly that operates at telecommunication window of 1550 nanometers. Low insertion loss of 0.5 decibels and bandwidth of 90 picometers over a 2000 nanometers operational range of detectors has been achieved.

optical filters↗
NASA NTRS1971

Experiments in spatial coherent optical filtering

Coherent optical techniques provide a means of processing entire pictures in parallel. Experiments were performed demonstrating the effectiveness of spatial frequency filtering in a coherent optical data processing system.

Larsen, R. K.↗
NASA NTRS1969

Proposed acousto-optic filter

Narrow band optical filter is electronically tunable over a large wavelength region. The filter utilizes collinear acousto-optic diffraction in an optically anisotropic media.

Harris, S. E.↗
NASA NTRS1973

Holography and Optical Filtering

Holography and optical filtering techniques for structural analysis, material tests, and astronomical observation - conference

Source record↗
NASA NTRS1992

A potassium Faraday anomalous dispersion optical filter

The characteristics of a potassium Faraday anomalous dispersion optical filter operating on the blue and near infrared transitions are calculated. The results show that the filter can be designed to provide high transmission, very narrow pass bandwidth, and low equivalent noise bandwidth. The Faraday anomalous dispersion optical filter (FADOF) provides a narrow pass bandwidth (about GHz) optical filter for laser communications, remote sensing, and lidar. The general theoretical model for the FADOF has been established in our previous paper. In this paper, we have identified the optimum operational conditions for a potassium FADOF operating on the blue and infrared transitions. The signal transmission, bandwidth, and equivalent noise bandwidth (ENBW) are also calculated.

Yin, B.↗
NASA NTRS1994

The Stark anomalous dispersion optical filter: The theory

The Stark anomalous dispersion optical filter is a wide-frequency-tunable ultra-narrow-bandwidth optical filter. The first theoretical investigation of this filter matched to the wavelength of a doubled Nd:YAG laser is reported. The calculations show that such a filter may provide above 80 percent transmission, and a noise equivalent bandwidth of 3 GHz.

Yin, B.↗
NASA NTRS1994

The Rb 780-nanometer Faraday anomalous dispersion optical filter: Theory and experiment

The Faraday anomalous dispersion optical filter may provide ultra-high background noise rejection for free-space laser communications systems. The theoretical model for the filter is reported. The experimental measurements and their comparison with theoretical results are discussed. The results show that the filter can provide a 56-dB solar background noise rejection with about a 2-GHz transmission bandwidth and no image degradation. To further increase the background noise rejection, a composite Zeeman and Faraday anomalous dispersion optical filter is designed and experimentally demonstrated.

Yin, B.↗
NASA NTRS1994

Ultrahigh-efficiency, very narrow-passband, tunable optical filter

Recently developed technologies have been uniquely integrated to produce optical filters with unprecedented performance. The precise design and fabrication of narrow-passband and high-efficiency optical filters with a central frequency of 532 nm are reported. Measurements with these filters demonstrate a performance that accurately mirrors the design specification, with one filter having a passband of 70 pm and an efficiency greater than 90% and the second filter having a passband of 7 pm and an efficiency greater than 80%.

Sandford, Stephen P.↗
NASA NTRS1993

Theoretical model for a Stark anomalous dispersion optical filter

A theoretical model for the first atomic Stark anomalous dispersion optical filter is reported. The results show the filter may serve as a widely tunable narrow bandwidth and high throughput optical filter for freespace laser communications and remote sensing.

Yin, B.↗