Search for dissertations about: "Spectroscopy heterodyne"

Showing result 1 - 5 of 10 swedish dissertations containing the words Spectroscopy heterodyne.

2. 1. Cavity enhanced optical sensing

   Author : Isak Silander; Ove Axner; Aleksandra Foltynowicz; Jong Chow; Umeå universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; Optical resonators; Fiber Laser; Parametric oscillators; Optical frequency comb; Infrared; Spectroscopy heterodyne; Spectroscopy molecular; Absorption; Dispersion; Lineshapes; Optical standards and testing; Refractivety measurements;

   Abstract : An optical cavity comprises a set of mirrors between which light can be reflected a number of times. The selectivity and stability of optical cavities make them extremely useful as frequency references or discri­mi­nators. READ MORE

4. 2. Wideband THz Mixers and Components for the Next Generation of Receivers for Radioastronomy

   Author : Cristian Daniel López; Chalmers tekniska högskola; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Spectroscopy; Heterodyne receivers; Finline; Superconductor-Insulator-Superconductor SIS mixers.; Waveguide-to-Substrate Transition; Waveguide twist;

   Abstract : In recent decades, there has been a growing interest in THz research, leading to substantial improvements in technology and the emergence of new applications. In particular, the ever-evolving field of radio astronomy instrumentation has been pushing the limits of millimeter and sub-millimeter technology boundaries, redefining the state-of-the-art for wideband low-noise receivers. READ MORE

5. 3. Advanced characterization techniques of photonic devices with frequency combs

   Author : Krishna Sundar Twayana; Chalmers tekniska högskola; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; electro-optic combs; multi-heterodyne; optical frequency domain spectroscopy; stepped-heterodyne; swept-wavelength interferometry; microcombs; waveguides; microresonators; frequency combs;

   Abstract : Integrated photonics has witnessed remarkable progress in the last decades. Measuring photonic devices in amplitude and phase provides insight into their performance. Swept wavelength interferometry is a prominent technique for the broadband characterization of the complex response. READ MORE

6. 4. Bayesian Inference for Microwave Diagnostics at Joint European Torus

   Author : Stefan Schmuck; Per Brunsell; Thomas Jonsson; Jakob Svensson; Laurie Porte; KTH; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; ECE; Bayesian; Fourier transform; spectroscopy; joint inference; length-scale; Gaussian process; microwave diagnostic; JET; Electrical Engineering; Elektro- och systemteknik;

   Abstract : The major goal of this thesis is to perform Bayesian inference jointly for electron kinetic profiles, a toroidal magnetic field correction, diagnostic sensitivities, and wall reflection properties given noisy measurements of four microwave diagnostics at the tokamak JET. Besides the measurements, this kind of inference considers prior knowledge, like profile length-scales, to update objectively the information about the physics parameters. READ MORE

7. 5. Fiber-laser-based noise-immune cavity-enhanced optical heterodyne molecular spectrometry

   Author : Aleksandra Foltynowicz; Ove Axner; Weidong Chen; Umeå universitet; []
   Keywords : 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;

   Abstract : 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). READ MORE