United States of America As Represented by the Secretary of the Air Force

Other

James R Gord

Sukesh Roy

Paul S Hsu

Robert P Lucht

Michael A Brown

Mikhail N Slipchenko

Thomas N Anderson

Rodolfo Barron-Jimenez

Thomas Walther

Jerald A Caton

Naibo Jiang

Gregory J Fiechtner

Steven W Buckner

Michael S Brown

Sherif F Hanna

Waruna Kulatilaka

Keith D Grinstead, Jr

William L Weaver

Systems and methods for measuring temperature in an environment by creating a first beam having an energy of about 50 mJ/pulse, and a pulse duration of about 100 ps. A second beam is also created, having an energy of about 2.3 mJ/pulse, and a pulse duration of about 58 ps. The first beam and the second beam are directed into a probe region, thereby expressing an optical output. Properties of the optical output are measured at a sampling rate of at least about 100 kHz, and temperature measurements are derived from the measured properties of the optical output. Such systems and methods can be used to measure temperature in environments exhibiting highly turbulent and transient flow dynamics.

Systems and methods for high-speed, spectroscopic, gas-phase thermometry

A low-repetition-rate (10-Hz), picosecond (ps) optical parametric generator (OPG) system produces higher energy output levels in a more robust and reliable system than previously available. A picosecond OPG stage is seeded at an idler wavelength with a high-power diode laser and its output at &#x2dc;566 nm is amplified in a pulsed dye amplifier (PDA) stage having two dye cells, resulting in signal enhancement by more than three orders of magnitude. The nearly transform-limited beam at &#x2dc;566 nm has a pulse width of &#x2dc;170 ps with an overall output of &#x2dc;2.3 mJ/pulse. A spatial filter between the OPG and PDA stages and a pinhole between the two dye cells improve high output beam quality and enhances coarse and fine wavelength tuning capability.

Nearly transform-limited, low-repetition-rate, picosecond optical parametric generator

A high energy UV fiber-coupled laser-induced fluorescence system is provided having a transmission component and a receiving component. The transmission component includes a laser source configured to produce high-energy UV pulses, a UV-enhanced fused-silica fiber coupled to the laser source, and optics coupled to the UV-enhanced fused-silica fiber for transmitting the high-energy UV pulses to a target area. The receiving component receives laser-induced florescence events from the target area and includes additional UV-enhanced fused-silica fiber coupled to optics and a receiving means.

All fiber coupled ultraviolet planar laser induced fluorescence detection system

An all-solid-state continuous-wave (cw) laser system for measurements of the absorption by the CO molecule of mid-infrared radiation in the 4.3-4.6 &#x3bc;m range is described, wherein a single-mode, tunable output of a 70 mW, 860-nm ECDL is difference frequency mixed with the output of a 550 mW diode-pumped cw Nd:YAG laser in a PPLN crystal to produce approximately 1 &#x3bc;W of tunable cw radiation at 4.5 &#x3bc;m.

Diode-laser-based mid-infrared absorption sensor for carbon monoxide

A triple-pump coherent anti-Stokes Raman scattering (CARS) system for simultaneous measurements of temperature and species concentrations with high spatial and temporal resolution is described, wherein four laser beams generate CARS signals near two distinct wavelengths exhibiting an NCARS signal along with the CARS signal from another target molecule, each pair of CARS signals generated over a relatively narrow wavelength region and captured with fixed-wavelength detection. Temperature and relative concentrations of the target species with respect to Nare extracted by fitting the measured CARS spectrum in each wavelength region.

Triple-pump coherent anti-Stokes Raman scattering system

A nitric oxide sensor and method is disclosed. The sensor is based on sum-frequency mixing of a tunable, 395-nm external cavity diode laser with a 532-nm diode-pumped intracavity-frequency-doubled Nd:YAG laser in a beta-barium-borate crystal. The output from the BBO crystal is ultraviolet radiation at 227 nm and is split using a 50&#x2014;50 beam splitter. Half of the radiation is directed into a reference photomultiplier tube, and the other half of the UV radiation is directed through the medium of interest and then directed into a signal photomultiplier tube. The output from the photomultiplier tubes is compared and the difference utilized to indicate the level of nitric oxide by absorption-based spectrosocpic techniques.

Nitric oxide sensor and method

A method for the quantitative determination of dissolved oxygen in a liquid fuel includes the steps of doping a sample of the fuel with a preselected concentration of a probe material including a luminophor which exhibits luminescence of wavelength which is quenched by oxygen dissolved in the fuel, illuminating the fuel with light from a coherent light source, such as a laser, of a wavelength which induces the luminescence in the luminophor, and thereafter measuring the change with time of the luminescence from the luminophor in the fuel and determing from the change with time of the luminescence the concentration of oxygen in the fuel.

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Dayton, OH, United States of America

James R Gord