摘要:
There is provided a system for remote pumping of a Raman fiber amplifier comprising a pump laser located remotely from the Raman fiber amplifier and a laserhead and one or more optical fibers to optically couple the high power pump light from the remote pump laser to the Raman fiber amplifier where a seed laser light is amplified wherein the pump laser for producing a high power laser light of a predetermined pump wavelength comprises a first fiber laser emitting light at the predetermined pump wavelength and one (second) or two (third) laser emitting light at a wavelength lower than the predetermined pump wavelength and multiplexed with light from the first laser into an optical fiber providing Raman gain at the predetermined pump wavelength to convert the second (and optionally also the third) laser light to light at the predetermined pump wavelength.
摘要:
The emittance value is a measure of an amount of energy expelled from a given surface area relative to a black-body reference. Depending on the specific coating a change in the emittance value is actively or passively effected. There are known active variable emittance thermal control coatings. However, such coatings are actually panels housing a mixture of both high and low emissivity materials that are electrically manipulated to control the emittance value of the panel. These “coatings” are classified as either electrochromic or electrophorectic. Both electrochromic and electrophorectic coatings require an applied voltage to cause a change in the emittance value of the coating. By contrast, aspects of the present invention do not include active variable emittance thermal control coatings. Aspects of the present invention do include passive variable emittance thermal control coatings and materials. In accordance with aspects of the present invention “passive” means that the variable emittance value changes in response to changes in the environment without active control (e.g. neither a voltage nor a current is applied). More specifically, in accordance with one aspect of the invention a passive variable emittance thermochromic material is provided that has a relatively low emittance value at low temperatures and a relatively high emittance value at high temperatures.
摘要:
A method and apparatus for non-contact determination of liquid concentrations such as the content of water, oil, dye, paint, fuel, glue, etc., in a moving or stationary mass of production such as wood, paper, powders, fabrics, sand, bricks, concrete, plants, and the like, or in other liquids such as oil spills in water, is provided. The method comprises measuring the passive emissivity of a substance, using an imaging radiometer. It has been found that an emissivity image may be used to quantify the liquid content in a substance. The invented method allows for non-contact, rapid and continuous in-line measurements.
摘要:
A figure-8 laser is configured in which gain in the uni-directional loop can be removed while maintaining mode-locked operation with gain only in the bi-directional nonlinear amplifying loop. Simplified self-starting and control over pulse characteristics by controlling gain in the bi-directional loop is made possible.
摘要:
A figure-8 laser is configured in which gain in the uni-directional loop can be removed while maintaining mode-locked operation with gain only in the bi-directional nonlinear amplifying loop. Simplified self-starting and control over pulse characteristics by controlling gain in the bi-directional loop is made possible.
摘要:
Good femtosecond fiber laser performance is achieved by producing picosecond Raman shifted pulses of sufficient intensity to undergo self-phase modulation (SPM), thus causing the pulses to advantageously spread spectrally, which then makes it possible to temporally compress the pulses with an optical compressor to produce femtosecond pulses with high peak power.
摘要:
There is described a passive variable emittance device comprising: a substrate having a receiving surface adapted to reflect radiations having a given wavelength; an intermediary layer deposited on the receiving surface of the substrate and being substantially transparent to the radiations having the given wavelength; and a thermochromic layer deposited on top of the intermediary layer, the thermochromic layer being substantially transparent to the radiations having the given wavelength for a first temperature below a given transition temperature, and presenting both reflection and absorption for the radiations for a second temperature above the given transition temperature, a total optical thickness for the intermediary and thermochromic layers being substantially equal to one quarter of the given wavelength so that radiations reflected by the thermochromic layer at the second temperature destructively interfere with radiations transmitted by the thermochromic and intermediary layers and reflected by the substrate in order to obtain a first emittance for the passive variable emittance device at the second temperature being greater than a second emittance for the passive variable emittance device at the first temperature.
摘要:
A self-healing material comprises a matrix embedded with micro-pockets of a healing-agent releasable by a crack in the matrix. The healing-agent is able to bond to the matrix to repair the crack. The healing-agent is contained in microcapsules. A corresponding catalyst for the healing-agent is embedded in the matrix and contained in a plurality of microcapsules as an emulsion. The emulsion comprises an oil, a perfluorated solvent, a hydrophobic ionic liquid, or mixtures thereof. A method of manufacturing the self-healing material comprises the steps of identifying an operational temperature range of the material, providing at least one substance as the healing-agent, which substance remaining substantially in a liquid state within the operational temperature range, identifying an operational evaporation rate of the healing-agent and providing the substance with a curing time according to the evaporation rate.
摘要:
A new transmission link configuration with remote Er post- and pre-amplifiers where pump power is shared between a pair of fibers carrying traffic in opposite directions is proposed. A budget increase of >4 dB is demonstrated.
摘要:
A new transmission link configuration with remote Er post- and pre-amplifiers where pump power is shared between a pair of fibers carrying traffic in opposite directions is proposed. A budget increase of >4 dB is demonstrated.