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Timestamp: 2019-04-26 00:47:13+00:00

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We demonstrate a broadband rapid scanning light source in the 3-μm region by using difference frequency generation (DFG). The DFG source consists of a module with quasi-phase-matched LiNbO3 ridge waveguides, a 1-μm-band wide swept range laser for the pump source, and a 1.5-μm continuous wave laser for the signal source. The sweep rate and the tuning bandwidth of this source are 20 kHz and 100 nm, respectively. This source enables us to evaluate the temperature dependence of absorbance of methane gas.
T. Töpfer, K. P. Petrov, Y. Mine, D. Jundt, R. F. Curl, and F. K. Tittel, Appl. Opt. 36, 8042 (1997).
S. Bartalini, S. Borri, and P. D. Natale, Opt. Express 17, 7440 (2009).
S. Borri, S. Bartalini, P. Cancio, I. Galli, G. Giusfredi, D. Mazzotti, and P. De Natale, Opt. Eng. 49, 111122 (2010).
K. Fujita, T. Edamura, N. Akikusa, A. Sugiyama, T. Ochiai, S. Furuta, A. Ito, M. Yamanishi, and H. Kan, Proc. SPIE 7230, 723016 (2009).
F. Kuhnemann, K. Schneider, A. Hecker, A. Martis, W. Urban, S. Schiller, and J. Mlynek, Appl. Phys. B 66, 741 (1998).
M. Abe, S. Kusanagi, Y. Nishida, O. Tadanaga, H. Takenouchi, and H. Sasada, Opt. Express 23, 21786 (2015).
F. C. D. Lucia, R. S. Harmon, K. L. McNesby, R. J. Winkel, and A. W. Miziolek, Appl. Opt. 42, 6148 (2003).
L. A. Kranendonk, X. An, A. W. Caswell, R. E. Herold, S. T. Sanders, R. Huber, J. G. Fujimoto, Y. Okura, and Y. Urata, Opt. Express 15, 15115 (2007).
M. Wu, E. Vail, G. Li, W. Yuen, and C. Chang-Hasnain, Electron. Lett. 31, 1671 (1995).
A. Silva and I. D. Lindsay, Appl. Phys. B 107, 685 (2012).
H. Sera, M. Abe, K. Iwakuni, S. Okubo, H. Inaba, F. L. Hong, and H. Sasada, Opt. Lett. 40, 5467 (2015).
T. Yanagawa, O. Tadanaga, Y. Nishida, H. Miyazawa, K. Magari, M. Asobe, and H. Suzuki, Opt. Lett. 31, 960 (2006).
D. H. Jundt, Opt. Lett. 22, 1553 (1997).
O. Tadanaga, T. Yanagawa, Y. Nishida, K. Magari, T. Umeki, M. Asobe, and H. Suzuki, J. Appl. Phys. 102, 033102 (2007).
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, J. Quant. Spectrosc. Radiat. Transfer 130, 4 (2013).
C. Akcay, P. Parrein, and J. P. Rolland, Appl. Opt. 41, 5256 (2002).
L. S. Rothman, J. Schroeder, and K. Tang, JavaHAWKS Manual (Harvard Smithsonian Center for Astrophysics, 2004).
Fig. 1. Experimental setup. ECLD, 1.5-μm-band external-cavity laser diode; SM, single mode fiber; FA, Er-doped fiber amplifier; WDM, wavelength division multiplexing fiber coupler; Col., collimate lens; InSb, liquid nitrogen cooled InSb detector; OBPF, optical bandpass filter; Osc., oscilloscope. Dotted lines indicate electric cables.
Fig. 2. Pump and signal wavelength combination curves that satisfy Δ k = 0 (center, red) and [ sin ( Δ k L / 2 ) / ( Δ k L / 2 ) ] 2 = 0.5 (upper and lower, blue) for a QPM bulk LN device with QPM periods of 30.3 μm. LN temperature is 19°C and L = 50 mm . Horizontal straight line is 1570.5 nm and vertical straight line is 1064 nm. Δ λ j is the bandwidth in wavelength ( j = p , s , i ). The subscripts indicate pump, signal and idler, respectively. When the margin of the DFG conversion is half of the peak power, the bandwidth is 129 nm in the 3-μm region when the signal at 1570.5 nm is constant, while that for the bandwidth of 1064 nm is only 7 nm. The cross shows the Δ k = 0 position against the signal at 1570.5 nm when we take the waveguide dispersion into account.
Fig. 3. Measured phase matching spectra. LN temperature is constant at 18.8°C. The thick (red) curve indicates a fixed signal wavelength. Pump wave is repeatedly swept. Swept time is the upper horizontal axis. The gray curve shows the phase matching curve of the fixed pump wavelength. The upper horizontal axis is only for the thick curve.
Fig. 4. Fine structure of the fundamental band ν 3 of methane. This spectrum was acquired by averaging 8 times. The inset is the arrowed absorption line [R(0)] expanded.
Fig. 5. Normalized (a) and calculated (b) spectra for methane ν 3 band spectra: (a) is measured at room temperature; (b) is assumed a Lorentzian lineshape with a linewidth 0.2 cm − 1 , a pressure of 70 Torr, and an absorption length of 40 cm at 296 K.
Fig. 6. Normalized (a) and calculated (b) spectra for methane ν 3 band spectra: (a) is measured by cooling the absorption cell with liquid nitrogen; (b) is assumed a Lorentzian lineshape with a linewidth 0.2 cm − 1 , a pressure of 70 Torr, and an absorption length of 30 cm at 77 K and 10 cm at 296 K.

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