Source: http://aoot.osa.org/oe/abstract.cfm?uri=oe-25-26-32386
Timestamp: 2019-04-24 09:53:24+00:00

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The hyperspectral absorption spectroscopy is attracting more and more attention as this technique enables continuous wavelength sweep over a whole absorption band, rather than one or several discrete absorption lines. Owing to the H2O possesses much stronger and more abundant absorption lines in the 2μm region, this work develop a widely tunable, narrow linewidth Tm-doped fiber laser around 1.87μm for the application of combustion diagnostics. The laser wavelength tuning range is designed from 1850 nm to 1890 nm to overlap the strong absorption band of H2O, and the laser linewidth is further narrowed to 0.04 nm by a fiber saturable absorber. With this laser system, demonstration experiments are implemented for the continuous detection of H2O absorption lines. Detailed absorption peaks of H2O from 1866 nm to 1879 nm are detected and well-resolved. The measured absorption spectrum agree well with the theoretical computation derived from HITRAN2012 database quantitatively, verifying this laser system ready for hyperspectral absorption applications.
M. A. Bolshov, Y. A. Kuritsyn, and Y. V. Romanovskii, “Tunable diode laser spectroscopy as a technique for combustion diagnostics,” Spectrochim. Acta B At. Spectrosc. 106, 45–66 (2015).
R. K. Hanson and D. F. Davidson, “Recent advances in laser absorption and shock tube methods for studies of combustion chemistry,” Prog. Energ. Combust. 44, 103–114 (2014).
W. W. Cai and C. F. Kaminski, “Tomographic absorption spectroscopy for the study of gas dynamics and reactive flows,” Prog. Energ. Combust. 59, 1–31 (2017).
C. S. Goldenstein, R. M. Spearrin, J. B. Jeffries, and R. K. Hanson, “Infrared laser-absorption sensing for combustion gases,” Prog. Energ. Combust. 60, 132–176 (2017).
B. Tao, Z. Hu, W. Fan, S. Wang, J. Ye, and Z. Zhang, “Novel method for quantitative and real-time measurements on engine combustion at varying pressure based on the wavelength modulation spectroscopy,” Opt. Express 25(16), A762–A776 (2017).
R. Sur, K. Sun, J. B. Jeffries, J. G. Socha, and R. K. Hanson, “Scanned-wavelength-modulation-spectroscopy sensor for CO, CO2, CH4and H2O in a high-pressure engineering-scale transport-reactor coal gasifies,” Fuel 150, 102–111 (2015).
Z. Qu, R. Ghorbani, D. Valiev, and F. M. Schmidt, “Calibration-free scanned wavelength modulation spectroscopy--application to H2O and temperature sensing in flames,” Opt. Express 23(12), 16492–16499 (2015).
A. Sepman, Y. Ögren, Z. C. Qu, H. Wiinikka, and F. M. Schmidt, “Real-time in situ multi-parameter TDLAS sensing in the reactor core of an entrained-flow biomass gasifier,” Proc. Combust. Inst. 36(3), 4541–4548 (2017).
T. Kraetschmer, Hyperspectral Lasers for Spectroscopic Measurements in the Near-infrared (Academic, University of Wisconsin-Madison, 2009).
R. Huber, M. Wojtkowski, and J. G. Fujimoto, “Fourier Domain Mode Locking (FDML): A new laser operating regime and applications for optical coherence tomography,” Opt. Express 14(8), 3225–3237 (2006).
R. Huber, D. C. Adler, and J. G. Fujimoto, “Buffered Fourier domain mode locking: Unidirectional swept laser sources for optical coherence tomography imaging at 370,000 lines/s,” Opt. Lett. 31(20), 2975–2977 (2006).
C. Jirauschek, B. Biedermann, and R. Huber, “A theoretical description of Fourier domain mode locked lasers,” Opt. Express 17(26), 24013–24019 (2009).
L. A. Kranendonk, X. An, A. W. Caswell, R. E. Herold, S. T. Sanders, R. Huber, J. G. Fujimoto, Y. Okura, and Y. Urata, “High speed engine gas thermometry by Fourier-domain mode-locked laser absorption spectroscopy,” Opt. Express 15(23), 15115–15128 (2007).
A. W. Caswell, S. Roy, X. An, S. T. Sanders, F. R. Schauer, and J. R. Gord, “Measurements of multiple gas parameters in a pulsed-detonation combustor using time-division-multiplexed Fourier-domain mode-locked lasers,” Appl. Opt. 52(12), 2893–2904 (2013).
L. Ma, X. Li, S. T. Sanders, A. W. Caswell, S. Roy, D. H. Plemmons, and J. R. Gord, “50-kHz-rate 2D imaging of temperature and H2O concentration at the exhaust plane of a J85 engine using hyperspectral tomography,” Opt. Express 21(1), 1152–1162 (2013).
S. Kobtsev and S. Smirnov, “Modelling of high-power supercontinuum generation in highly nonlinear, dispersion shifted fibers at CW pump,” Opt. Express 13(18), 6912–6918 (2005).
C. F. Kaminski, R. S. Watt, A. D. Elder, J. H. Frank, and J. Hult, “Supercontinuum radiation for applications in chemical sensing and microscopy,” Appl. Phys. B 92(3), 367–378 (2008).
K. Sumimura, Y. Genda, T. Ohta, K. Itoh, and N. Nishizawa, “Quasi-supercontinuum generation using 1.06 μm ultrashort-pulse laser system for ultrahigh-resolution optical-coherence tomography,” Opt. Lett. 35(21), 3631–3633 (2010).
J. W. Walewski and S. T. Sanders, “High-resolution wavelength-agile laser source based on pulsed super-continuum,” Appl. Phys. B 79(4), 415–418 (2004).
R. S. Watt, C. F. Kaminski, and J. Hult, “Generation of supercontinuum radiation in conventional single-mode fibre and its application to broadband absorption spectroscopy,” Appl. Phys. B 90(1), 47–53 (2008).
J. Hult, R. S. Watt, and C. F. Kaminski, “High bandwidth absorption spectroscopy with a dispersed supercontinuum source,” Opt. Express 15(18), 11385–11395 (2007).
T. Werblinski, F. Mittmann, M. Altenhoff, T. Seeger, L. Zigan, and S. Will, “Temperature and water mole fraction measurements by time-domain-based supercontinuum absorption spectroscopy in a flame,” Appl. Phys. B 118(1), 153–158 (2015).
T. Werblinski, S. R. Engel, R. Engelbrecht, L. Zigan, and S. Will, “Temperature and multi-species measurements by supercontinuum absorption spectroscopy for IC engine applications,” Opt. Express 21(11), 13656–13667 (2013).
Y. Sych, R. Engelbrecht, B. Schmauss, D. Kozlov, T. Seeger, and A. Leipertz, “Broadband time-domain absorption spectroscopy with a ns-pulse supercontinuum source,” Opt. Express 18(22), 22762–22771 (2010).
N. Göran Blume and S. Wagner, “Broadband supercontinuum laser absorption spectrometer for multiparameter gas phase combustion diagnostics,” Opt. Lett. 40(13), 3141–3144 (2015).
N. G. Blume, V. Ebert, A. Dreizler, and S. Wagner, “Broadband fitting approach for the application of supercontinuum broadband laser absorption spectroscopy to combustion environments,” Meas. Sci. Technol. 27(1), 015501 (2016).
L. S. Rothman, I. E. Gordon, Y. Babikov, A. Barbe, D. C. Benner, P. F. Bernath, M. Birk, L. Bizzocchi, V. Boudon, L. R. Brown, A. Campargue, K. Chance, E. A. Cohen, L. H. Coudert, V. M. Devi, B. J. Drouin, A. Fayt, J. M. Flaud, R. R. Gamache, J. J. Harrison, J. M. Hartmann, C. Hill, J. T. Hodges, D. Jacquemart, A. Jolly, J. Lamouroux, R. J. Le Roy, G. Li, D. A. Long, O. M. Lyulin, C. J. Mackie, S. T. Massie, S. Mikhailenko, H. S. P. Müller, O. V. Naumenko, A. V. Nikitin, J. Orphal, V. Perevalov, A. Perrin, E. R. Polovtseva, C. Richard, M. A. H. Smith, E. Starikova, K. Sung, S. Tashkun, J. Tennyson, G. C. Toon, V. G. Tyuterev, and G. Wagner, “The HITRAN2012 molecular spectroscopic database,” J. Quant. Spectrosc. Radiat. Transf. 130, 4–50 (2013).
T. F. Refaat, U. N. Singh, J. Yu, M. Petros, S. Ismail, M. J. Kavaya, and K. J. Davis, “Evaluation of an airborne triple-pulsed 2 μm IPDA lidar for simultaneous and independent atmospheric water vapor and carbon dioxide measurements,” Appl. Opt. 54(6), 1387–1398 (2015).
F. Gibert, P. H. Flamant, D. Bruneau, and C. Loth, “Two-micrometer heterodyne differential absorption lidar measurements of the atmospheric CO2 mixing ratio in the boundary layer,” Appl. Opt. 45(18), 4448–4458 (2006).
U. N. Singh, B. M. Walsh, J. Yu, M. Petros, M. J. Kavaya, T. F. Refaat, and N. P. Barnes, “Twenty years of Tm:Ho:YLF and LuLiF laser development for global wind and carbon dioxide active remote sensing,” Opt. Mater. Express 5(4), 827–837 (2015).
A. Stark, L. Correia, M. Teichmann, S. Salewski, C. Larsen, V. M. Baev, and P. E. Toschek, “Intracavity absorption spectroscopy with thulium-doped fibre laser,” Opt. Commun. 215(1-3), 113–123 (2003).
R. J. De Young and N. P. Barnes, “Profiling atmospheric water vapor using a fiber laser lidar system,” Appl. Opt. 49(4), 562–567 (2010).
K. Bremer, A. Pal, S. Yao, E. Lewis, R. Sen, T. Sun, and K. T. V. Grattan, “Sensitive detection of CO2 implementing tunable thulium-doped all-fiber laser,” Appl. Opt. 52(17), 3957–3963 (2013).
M. M. Tao, B. Tao, T. Yu, Z. B. Wang, G. B. Feng, and X. S. Ye, “Output characteristics of tunable Tm-doped fiber lasers,” Infrared Laser Eng. 45(12), 1205002 (2016).
Fig. 1 Panel (a): the schematic diagram of the laser system. Panel (b): nominal tuning characteristics of the FP filter. WDM: wavelength division multiplex; TDF: Tm-doped fiber; OC: output coupler; ISO: isolator; THDF: Tm-Ho codoped fiber; FSR: free spectral range.
Fig. 2 Spectral linewidth of the laser system at 500 mW pump and 5 V FP filter driving voltage. Panel (a): without THDF. Panel (b): with 0.28 m THDF.
Fig. 3 The output power and wavelength tuning range of the laser system. Panel (a): the output power as a function of the launched pump power. Panel (b): the output wavelength as a function of the driving voltage, the inset gives the tuning range and a typical output spectrum.
Fig. 4 Experimental setup for the water absorption lines detection.
Fig. 5 Panel (a): the measured absorption signals in 10 periods. Panel (b): the measured absorption signals in one period. The red solid line represents the absorbed laser intensity, and the blue dashed line is the base line derived from the reference laser.
Fig. 6 Panel (a): the comparison between the measured absorption spectrum and the theoretical absorption spectrum. Panel (b): the relation between the output laser wavelength and the scanning time.
Fig. 7 Panel (a): the comparison of absorption coefficients between the simulation values based on HITRAN2012 database and the measured results. Panel (b): residual plot between the calculated spectrum and the measured spectrum. Pane (c): the enlarged view of the dashed border in Fig. 7(a) and the simulation spectrum with three different laser linewidths. Panel (d): residual plots for the enlarged view at different laser linewidths.
Fig. 8 Measured spectrum of successive measurements in 4 seconds.

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