TY - GEN
T1 - Wavelength-agile coherent tunable mid-IR ZGP-OPO source and its applications
AU - Miyamoto, Katsuhiko
AU - Abedin, Kazi Monowar
AU - Ito, Hiromasa
PY - 2007
Y1 - 2007
N2 - We report the demonstration of a wavelength-agile coherent tunable mid-infrared (IR) ZnGeP2 (ZGP) optical parametric oscillator (OPO). The mid-IR wavelength was tuned by varying the KTiOPO4 (KTP) OPO pumping wavelength, while the ZGP crystal angle remained fixed. The wavelength of pump OPO was controlled by changing the KTP crystals angle using a Galvano-optical beam scanner. Our mid-IR source can jump to a arbitrary wavelength without scanning through the intermediate wavelengths. A nonlinear optical crystal ZGP is suitable for OPOs in the mid-IR region. In most cases of mid-IR light generation using an OPO, the wavelength tuning is achieved by controlling the phase-matching angle or temperature of the nonlinear optical crystal. However, there are several disadvantages of this method including the walk-off angle, beam pass instability, refraction losses due to the high refractive index of ZGP (n-3.1), slow tuning rate, and so forth. Therefore, we developed a 2-μm-band pump-wavelength tunable mid-IR ZGP-OPO source. The mid-IR wavelength from the ZGP-OPO could be tuned from 5 to 9.8 μm, when the pump wavelength was controlled from 1.95 to 2.3 μm. The output pulse energy at 8μm was 1.3mJ/pulse at repetition rate of 30Hz. As an application of random wavelength accessibility, we could achieve the real-time measurement of phase change (solidification) of candle wax by measuring the change of absorption at two arbitrary wavelengths. We selected two wavelengths on the spectrum where significant changes of absorption upon solidification were detected and performed two-wavelength absorption measurements as the sample is allowed to cool from melted state.
AB - We report the demonstration of a wavelength-agile coherent tunable mid-infrared (IR) ZnGeP2 (ZGP) optical parametric oscillator (OPO). The mid-IR wavelength was tuned by varying the KTiOPO4 (KTP) OPO pumping wavelength, while the ZGP crystal angle remained fixed. The wavelength of pump OPO was controlled by changing the KTP crystals angle using a Galvano-optical beam scanner. Our mid-IR source can jump to a arbitrary wavelength without scanning through the intermediate wavelengths. A nonlinear optical crystal ZGP is suitable for OPOs in the mid-IR region. In most cases of mid-IR light generation using an OPO, the wavelength tuning is achieved by controlling the phase-matching angle or temperature of the nonlinear optical crystal. However, there are several disadvantages of this method including the walk-off angle, beam pass instability, refraction losses due to the high refractive index of ZGP (n-3.1), slow tuning rate, and so forth. Therefore, we developed a 2-μm-band pump-wavelength tunable mid-IR ZGP-OPO source. The mid-IR wavelength from the ZGP-OPO could be tuned from 5 to 9.8 μm, when the pump wavelength was controlled from 1.95 to 2.3 μm. The output pulse energy at 8μm was 1.3mJ/pulse at repetition rate of 30Hz. As an application of random wavelength accessibility, we could achieve the real-time measurement of phase change (solidification) of candle wax by measuring the change of absorption at two arbitrary wavelengths. We selected two wavelengths on the spectrum where significant changes of absorption upon solidification were detected and performed two-wavelength absorption measurements as the sample is allowed to cool from melted state.
KW - Frequency conversion
KW - Mid-IR
KW - Optical parametric oscillation
KW - ZnGeP
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U2 - 10.1117/12.723240
DO - 10.1117/12.723240
M3 - Conference contribution
AN - SCOPUS:36048942339
SN - 0819467103
SN - 9780819467102
T3 - Proceedings of SPIE - The International Society for Optical Engineering
BT - Nonlinear Optics and Applications II
T2 - Nonlinear Optics and Applications II
Y2 - 16 April 2007 through 18 April 2007
ER -