Sökning: "Ove Axner"

Visar resultat 6 - 10 av 18 avhandlingar innehållade orden Ove Axner.

1. 6. Further development of NICE-OHMS : – an ultra-sensitive frequency-modulated cavity-enhanced laser-based spectroscopic
 technique for detection of molecules in gas phase

   Författare :Patrick Ehlers; Ove Axner; Joakim Bood; Umeå universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NICE-OHMS; Frequency Modulation; Cavity Enhancement; Molecular Spectroscopy; fysik; Physics;

   Sammanfattning : Noise-immune cavity-enhanced optical heterodyne molecular spectroscopy, NICE-OHMS, is a laser-based spectroscopic detection technique that comprises the concepts of frequency modulation (FM, for reduction of 1/f-noise by detecting the signal at a high frequency) and cavity enhancement (CE, for a prolongation of the optical path length) in a unique way. Properly designed, this gives the technique an intrinsic immunity against the frequency-to-noise conversion that limits many other types of CE techniques. LÄS MER

3. 7. A sub-5 fs 100 TW optical parametric synthesizer

   Författare :Peter Fischer; Laszlo Veisz; Ove Axner; Cord L. Arnold; Umeå universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Optical parametric amplification OPA ; optical parametric synthesizer OPS optimization; energy stability; carrier envelop phase stability; temporal intensity contrast; saturation; fewcycle; tera watt; fysik; Physics;

   Sammanfattning : State-of-the-art ultrashort light sources in the visible and near-infrared spectral regions provide direct access to the femtosecond realm, thereby enabling understanding and control of electronic processes within matter. On the other hand, ultra-intense light pulses lead to the emergence of relativistic electron motion and many related phenomena, such as electron & ion acceleration and high-order harmonic generation in plasmas. LÄS MER

4. 8. Fiber-laser-based noise-immune cavity-enhanced optical heterodyne molecular spectrometry

   Författare :Aleksandra Foltynowicz; Ove Axner; Weidong Chen; Umeå universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; absorption spectrometry; frequency modulation; cavity enhancement; NICE-OHMS; Laser frequency stabilization; fiber laser; Fabry-Perot cavities; sub-Doppler spectroscopy; trace gas detection; Physics; Fysik; Molecular physics; Molekylfysik; fysik; Physics;

   Sammanfattning : Noise-immune cavity-enhanced optical heterodyne molecular spectro-metry (NICE-OHMS) is one of the most sensitive laser-based absorption techniques. The high sensitivity of NICE-OHMS is obtained by a unique combination of cavity enhancement (for increased interaction length with a sample) with frequency modulation spectrometry (for reduction of noise). LÄS MER

5. 9. Fabry-Pérot based refractometry : development of a transportable refractometer for assessment of gas pressure

   Författare :Clayton Forssén; Ove Axner; Isak Silander; Martin Zelan; Leslie Pendrill; Umeå universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; fabry-pérot; refractometry; optical resonator; transportable; pressure standard; gamor; pressure; metrology; ring comparison; si; pascal; quantumpascal; fysik; Physics;

   Sammanfattning : A unified description of physical phenomena through measurement science is one of the foundational pillars in a global society. The International System of Units (SI) is the most widely used system of units and since its redefinition in 2019, all units encompassed by it are based on fundamental physical constants. LÄS MER

7. 10. 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