Measurement of the pressure broadening coefficients of the oxygen A-band using a low cost, polarization stabilized, widely tunable vertical-cavity surface-emitting laser
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Vertical-cavity surface-emitting lasers (VCSELs) are used for oxygen monitoring via tunable diode laser spectroscopy at 760 nm wavelength. For the desired application, novel polarization-stable laser diodes based on AlGaAs were developed. We present measurements of the pressure-broadening coefficients of the electric dipole forbidden oxygen A-band b 1 Σ + g → X 3 Σ + g transition at 760 nm. The time the pressure-broadening coefficients were determined with a temperature tuned VCSEL. Generally temperature tuning has the disadvantage of frequent mode-hops, but the advantage of a wider tuning range in comparison to current tuning. Because of special techniques of polarization stabilization with a combination of a dielectric surface grating and a surface relief the VCSELs have a mode hop-free tuning range of more than 7 nm and a sidemode suppression of more than 30 dB. This provides a low cost laser diode system with a wide tuning range, which enables the possibility of simultaneous measurement of temperature, pressure and oxygen concentration in air, high pressure measurements and also a higher accuracy of oxygen concentration measurements.
KeywordsAbsorption Line Rotational Quantum Number Collision Partner Wide Tuning Range Temperature Tuning
The authors gratefully acknowledge Andreas Kürzinger, Sven Rademacher, Marcus Braun, Armin Lambrecht, and Susanne Hartwig for technical support.
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