Abstract book - Prof. Per Jensen, Ph.D. - Bergische Universität ...

Poster session, H28 141High signal-to-noise ratio line-shape measurements of the oxygen Bband by PDH-locked FS-CRDSAgata Cygan 1 , Daniel Lisak 1 , Szymon Wójtewicz 1 , Jolanta Domysławska 1 , JosephT. Hodges 2 , Ryszard S. Trawiński 1 , Roman Ciuryło 11 Instytut Fizyki, Uniwersytet Mikołaja Kopernika, Grudziądzka 5/7 87-100, Toruń,Poland, szymon@fizyka.umk.pl; 2 National Institute of Standards and Technology, 100Bureau Drive, Gaithersburg, Maryland 20899, USAWe present an extremely high signal-to-noise ratio measurements of spectral lineshapes. Our Pound-Drever-Hall (PDH) locked frequency-stabilized cavity ring-downspectrometer (FS-CRDS) 1 provides high spectral resolution and low detection limit. Theproblem of unexpected PDH-lock breaking during high-repetition rate ring-down eventsgeneration was solved thanks to an active control of the PDH error signal offset 2 whichassured more reliable and faster work of our spectrometer. Possible extension of laserlight switching-off time, between consecutive ring-down events, up to 1 ms is shown.An exceptionally precise measurements of absorption line shapes are demonstrated onexample of rovibronic transitions of the 16 O 2 B band near λ = 689 nm 3,4 . Obtainedsignal-to-noise ratio of 220000:1 and a minimum detectable absorption coefficient of2.4 × 10 −11 cm −1 corresponds to the lowest line intensity measurable by our setup ofapproximately 1.3 × 10 −30 cm −1 /(molecule cm −2 ) 5 . The detection limit of ourspectrometer was tested on example of weak oxygen line having intensity of 2.716 ×10 −29 cm −1 /(molecule cm −2 ). Careful analysis of the data revealed a subtle line-shapeasymmetry that could be explained by the speed dependence of the collisional shift. Theinfluence of slowly drifting etaloning effects on the precision of the line-shape analysisis presented. The precise line-shape measurements combined with sophisticated dataanalysis are crucial for such experiments as accurate determination of the Boltzmannconstant by optical methods 6,7 .The research is part of the program of the National Laboratory FAMO in Toruń, Poland,and is partially supported by the Foundation for Polish Science TEAM Project cofinancedby the EU European Regional Development Fund. A. Cygan is supported bythe Polish NCN, Project No. N N202 239240.Cygan A.Lisak D.Wojtewicz S.Domyslawska J.Hodges J.T.Trawinski R.S.Ciurylo R.References[1] A. Cygan, D. Lisak, P. Masłowski, K. Bielska, S. Wójtewicz, J. Domysławska, R. S.Trawiński, R. Ciuryło, H. Abe, J. T. Hodges, Rev. Sci. Instrum. 82, 063107 (2011).[2] A. Cygan, D. Lisak, S. Wójtewicz, J. Domysławska, R. S. Trawiński, R. Ciuryło,Meas. Sci. Technol. 22, 115303 (2011).[3] D. Lisak, P. Masłowski, A. Cygan, K. Bielska, S. Wójtewicz, M. Piwiński, J. T.Hodges, R. S. Trawiński, R. Ciuryło, Phys. Rev. A 81, 042504 (2010).[4] S. Wójtewicz, D. Lisak, A. Cygan, J. Domysławska, R. S. Trawiński, R. Ciuryło,Phys. Rev. A 84, 032511 (2011).[5] A. Cygan, D. Lisak, S. Wójtewicz, J. Domysławska, J. T. Hodges, R. S. Trawiński,R. Ciuryło, Phys. Rev. A 85, 022508 (2012).[6] A. Cygan, D. Lisak, R. S. Trawiński, R. Ciuryło, Phys. Rev. A 82, 032515 (2010).[7] A. Castrillo, M. D. DeVizia, L. Moretti, G. Galzerano, P. Laporta, A. Merlone, L.Gianfrani, Phys. Rev. A 84, 032510 (2011).