Utilization of fiber loop ring down technique for sensing applications

Download

index.pdf

Date

2017

Author

Yolalmaz, Alim

Metadata

Show full item record

Item Usage Stats

278
views

167
downloads

Fiber loop ring down (FLRD) spectroscopy is based on multiple interaction of laser light with sample/analyte. It is evolved from cavity ring down spectrometer with addition of optical fiber. Measurement accuracy rises with multiple interactions and this enhances the minimum detection limit compared to other spectrometers using single pass interaction such as FTIR, UV-VIS spectrometer. The other advantages of this technique are its insensitivity to laser fluctuation and detector performance. In this study, three FLRD set-ups were constructed with two laser sources at 800 and 1534 nm. Sensor regions were designed with two interaction methods as transmission and scattering and optimization for measurement parameters and probe structure were performed. The spectrometers’ parameters were examined with chemicals such as ethanol, acetone, toluene, acetylene gas, nitrogen gas. The response of the spectrometers to sample/analyte were investigated and limitations were discussed. Finally, the performance of the spectrometers was compared with the literature.

Subject Keywords

Fibers., Detectors., Microtechnology., Laser spectroscopy.

URI

http://etd.lib.metu.edu.tr/upload/12621182/index.pdf
https://hdl.handle.net/11511/26658

Collections

Graduate School of Natural and Applied Sciences, Thesis

Suggestions

OpenMETU
Core

Applications in broadband THz spectroscopy towards material studies Türkşen, Zeynep; Altan, Hakan; Department of Physics (2011) The purpose of this work was to construct and analyze a THz time domain spectroscopy (THz-TDS) system by using a nanojoule energy per pulse ultrafast laser (non-amplified ultrafast laser or oscillator) source and a non-linear optical generation method for THz generation. First a THz-TDS system, which uses photoconductive antenna (PCA) method for THz generation, was built to understand the working principles of these types of systems. This THz-TDS system which used PCA for generation and a 2mm thick <110> Zn...
Fiber loop ring down spectroscopy for trace chemical detection Cengiz, Betül; Danışman, Mehmet Fatih; Esentürk, Okan; Department of Chemistry (2013) Fiber loop ring down (FLRD) spectroscopy is a sensitive spectroscopic technique that is based on absorption and it is convenient for trace chemical detection. Different FLRD systems are being improved in order to increase their sensitivity. In FLRD spectroscopy, detection of a sample is done by measuring of a leaking light at each trip within an optical cavity. Intensity of leaking light has an exponential decay where it is reduced by absorption of sample and scattering of light. In this project, two FLRD s...
Thermal characterisation of quantum cascade lasers with Fabry Perot modes Gundogdu, Sinan; Pisheh, Hadi Sedaghat; Demir, Abdullah; Guenoven, Mete; AYDINLI, ATİLLA; Sirtori, Carlo (2018-04-26) Quantum cascade lasers are coherent light sources that rely on intrersubband transition in periodic semiconductor quantum well structures. They operate at frequencies from mid-infrared to terahertz. In cases of long wavelength and typical low thermal conductivity of the active region, temperature rise in the active region during operation is a major concern. Thermal conductivity of QCL epi-layers differ significantly from the values of bulk semiconductors and measurement of the thermal conductivity of epi-l...
Silicon microspheres for optical modulation applications Yüce, Emre; GÜRLÜ, Oguzhan; SERPENGÜZEL, Ali (2009-05-06) A silicon microsphere coupled to a silica optical fiber half coupler is excited using a diode laser operating at 1.55 mu m. The transmitted and the 90 degrees elastically scattered light signals are modulated with an electrical square wave applied to the silicon microsphere.
Fiber loop ring down spectrometer optical based sensor for trace chemical detection Yolalmaz, Alim; Esentürk, Okan; Danışman, Mehmet Fatih; Hanifehpour, Farhad (2016-04-11) Fiber loop ring down (FLRD) is a time domain multi-functional sensing, characterization, detection technique. FLRD technique is used to sense temperature, pressure, strain, biological cells, refractive index, and chemical species. FLRD has high accuracy, high selectivity, ability of remote control and rapid response. In this project, two FLRD spectrometers working at 800 nm (figure 1) and 1535 nm (figure 2) were set up for sensing different chemical analytes like C2H2, CO2, Ar, N2, DMSO, DMF, H2O, C2H6O, C3...

Citation Formats

A. Yolalmaz, “Utilization of fiber loop ring down technique for sensing applications,” M.S. - Master of Science, Middle East Technical University, 2017.