Utilization of fiber loop ring down technique for sensing applications

Yolalmaz, Alim
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. 


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Ertaş, Gülay (Royal Society of Chemistry (RSC), 2003-01-01)
The transient extension (TEx) chamber was developed to provide a simple means of lengthening an electrothermal vaporizer (ETV) signal for the purpose of obtaining a full mass scan from a single ETV firing with inductively coupled plasma mass spectrometry (ICPMS) detection. The TEx chamber was used for quantitative analysis of natural water (NIST SRM 1640). Quantitative analysis was done for Co, Be, Pb, Sb and Cd. Detection limits for the five elements tested with the TEx chamber were in the 1-10 mug L-1 ran...
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Ensemble Monte Carlo simulation of quantum well infrared photodetectors
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Quantum well infrared photodetectors (QWIPs) have recently emerged as a potential alternative to the conventional detectors utilizing low bandgap semiconductors for infrared applications. There has been a considerable amount of experimental and theoretical work towards a better understanding of QWIP operation, whereas there is a lack of knowledge on the underlying physics. This work provides a better understanding of QWIP operation and underlying physics through particle simulations using the ensemble Monte...
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...
Development of a parylene bonding based fabrication method for MEMS gravimetric resonant based mass sensors
Gökçe, Furkan; Külah, Haluk; Department of Electrical and Electronics Engineering (2017)
This thesis reports development of a parylene bonding based fabrication method for MEMS gravimetric resonant based mass sensors that are integrated with microfluidics for real-time detection when there is a liquid flow through the microfluidic channels. Parylene bonding has been optimized by conducting several bare bonding experiments. The optimized bonding takes place at 250ºC, in vacuum (1 mTorr) and with 2000 N of vertical piston force for 1 hour. The average shear bonding strength is 15.58 MPa for the o...
Citation Formats
A. Yolalmaz, “Utilization of fiber loop ring down technique for sensing applications,” M.S. - Master of Science, Middle East Technical University, 2017.