Sökning: "mid infrared detection"

Visar resultat 1 - 5 av 30 avhandlingar innehållade orden mid infrared detection.

1. 1. Mid- and near-infrared NICE-OHMS : techniques for ultra-sensitive detection of molecules in gas phase

   Författare :Thomas Hausmaninger; Ove Axner; Kyle Crabtree; Umeå universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; spectrometry; NICE-OHMS; trace gas detection; acetylene; methane; isotopologues; near-infrared; mid-infrared; shot-noise; optical parametric oscillator; teknisk fysik med inriktningen mikrosystemteknik; engineering science with specialization in microsystems technology;

   Sammanfattning : Noise-immune cavity-enhanced optical heterodyne molecular spectrometry (NICE-OHMS) is a technique for ultra-sensitive detection of molecular absorption and dispersion. For highest performance, the technique combines cavity enhancement (CE) with frequency modulation (FM); while the former increases the effective interaction length between the light and the analyte by several orders of magnitudes, the latter removes the in-coupling of 1/f noise and makes the signals background free. LÄS MER

3. 2. Upconversion Detection for Improved Nonlinear Mid-infrared Spectroscopy in Flames

   Författare :Rasmus Lyngbye Pedersen; Förbränningsfysik; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; infrared; upconversion; degenerate four wave mixing; hydrogen cyanide; polarisation spectroscopy;

   Sammanfattning : This thesis deals with the addition of upconversion detection to non-linear mid-infrared laser spectroscopy techniques. The techniques investigated here are degenerate four wave mixing (DFWM) and infrared polarization spectroscopy (IRPS). LÄS MER

4. 3. Mid-infrared photonic devices for on-chip optical gas sensing

   Författare :Floria Ottonello Briano; Kristinn B. Gylfason; Delphine Marris-Morini; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; mid-infrared; mid-IR; photonics; silicon photonics; gas sensing; optical sensing; optical gas sensing; spectroscopy; absorption; dispersion; carbon dioxide; CO2; CO2 sensing; trace gas; ethanol sensing; alcohol sensing; waveguide; photonic waveguide; ring resonator; nanowire; nanoheater; emitter; thermal source; bolometer; microbolometer; thermal detector; high frequency; 3 omega method; plasmonic; platinum; Kanthal; silicon-on-insulator; micro-electro-mechanical systems MEMS ; microfabrication; microsystems; microtechnology; nanotechnology; Optik och fotonik; Optics and Photonics; Electrical Engineering; Elektro- och systemteknik;

   Sammanfattning : Gas detection is crucial in a wide range of fields and applications, such as safety and process control in the industry, atmospheric sciences, and breath diagnostics. Optical gas sensing offers some key advantages, compared to other sensing methods such as electrochemical and semiconductor sensing: high specificity, fast response, and minimal drift. LÄS MER

5. 4. Novel on-line mid infrared detection strategies in capillary electrophoretic systems

   Författare :Malin Kölhed; Bo Karlberg; Sven P. Jacobsson; Andre' J. Sommer; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; on-line hyphenation; mid infrared detection; capillary electrophoresis; FTIR; quantum cascade laser; aqueous samples; Analytical chemistry; Analytisk kemi;

   Sammanfattning : Infrared absorption spectra can provide analytically useful information on a large variety of compounds, ranging from small ions to large biological molecules. In fact, all analytes that possess a dipole moment that changes during vibration are infrared-active. The infrared (IR) spectrum can be subdivided into far-, mid- and near- regions. LÄS MER

7. 5. Development and Application of Non-linear Mid-infrared Laser Spectroscopy for Combustion Diagnostics

   Författare :Zhiwei Sun; Förbränningsfysik; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Degenerate four-wave mixing; Polarization spectroscopy; Mid-infrared; Non-linear laser spectroscopy; Laser diagnostics; Combustion; Flame; HITRAN; Concentration; Temperature; Fysicumarkivet A:2012:Sun;

   Sammanfattning : The work reported in this thesis involved the development and application of two novel infrared non-linear laser techniques, namely mid-infrared polarization spectroscopy (IRPS) and mid-infrared degenerate four-wave mixing (IR-DFWM) to combustion diagnostics. These two techniques meet the needs of species concentration detection in combustion environments, especially for those species lacking accessible electronic (one-photon) transitions in the ultraviolet (UV) or visible spectral region. LÄS MER