caa a22 4500 445372591 CHVBK 20180317142952.0 cr unu---uuuuu 170323e20110201xx s 000 0 eng 10.1007/s00340-010-4002-1 doi (NATIONALLICENCE)springer-10.1007/s00340-010-4002-1 VCSEL based Faraday rotation spectroscopy with a modulated and static magnetic field for trace molecular oxygen detection [Elektronische Daten] [S. So, E. Jeng, G. Wysocki] Faraday Rotation Spectroscopy (FRS) is a useful technique for quantification of paramagnetic trace gases with significantly higher sensitivity when compared to direct absorption techniques. Our prototype system based on the openPHOTONS sensor core measures the concentration of molecular oxygen (O2) in the A band using a 763-nm vertical cavity surface emitting laser. We provide detailed analysis of two measurement methods based on FRS using the same sensor configuration: one with a modulated magnetic field, and one with a static magnetic field in combination with wavelength modulation. Our spectra signal-to-noise ratios agree well with our simulations via modeling of the FRS signal. For alternating magnetic field, we achieve an equivalent minimum detectable absorption (MDA) of $8.86\times 10^{-7}/\mathrm{Hz}^{\frac{1}{2}}$ resulting in a minimum detection limit of 30 ppmv⋅m/$\mathrm{Hz}^{\frac{1}{2}}$ of O2, limited by detector noise and laser noise. For the same system configuration in the static field case, parasitic etalon fringes limited the MDA to $4.8\times 10^{-6}/\mathrm{Hz}^{\frac{1}{2}}$. In both cases, we describe methods to improve signal-to-noise ratio based on our data and models. Springer-Verlag, 2010 So S. Electrical Engineering Department, Princeton University, Engineering Quad, Princeton, NJ, USA aut Jeng E. Electrical Engineering Department, Princeton University, Engineering Quad, Princeton, NJ, USA aut Wysocki G. Electrical Engineering Department, Princeton University, Engineering Quad, Princeton, NJ, USA aut Applied Physics B Springer-Verlag 102/2(2011-02-01), 279-291 0946-2171 102:2<279 2011 102 340 https://doi.org/10.1007/s00340-010-4002-1 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s00340-010-4002-1 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- So S. Electrical Engineering Department, Princeton University, Engineering Quad, Princeton, NJ, USA aut NATIONALLICENCE 700 1- Jeng E. Electrical Engineering Department, Princeton University, Engineering Quad, Princeton, NJ, USA aut NATIONALLICENCE 700 1- Wysocki G. Electrical Engineering Department, Princeton University, Engineering Quad, Princeton, NJ, USA aut NATIONALLICENCE 773 0- Applied Physics B Springer-Verlag 102/2(2011-02-01), 279-291 0946-2171 102:2<279 2011 102 340 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer