Development of a mid-infrared tunable optical parametric oscillator pumped by a Q-switched Tm,Ho:YAG laser

A compact and high-energy pulsed mid-infrared laser using an optical parametric oscillator (OPO) has been developed using a diode-pumped and Q-switched Tm,Ho:YAG ceramic laser with a wavelength of 2.09 μm as a pump source. A singly-resonant OPO with a 20 mm long AgGaSe2 crystal was used, and the crystal was set at an angle normal to the pump beam. The output idler pulse energy was up to about 200 μJ with the pump energy of about 6 mJ for both the type I and type II phase matching conditions. The wavelength of the idler pulses was 5.97 and 6.37 μm for type I and type II, respectively. The output characteristics predicted using a model calculation were in good agreement with the experimental results. It is suggested that the output idler pulse energy in the experiment is limited by the surface damage threshold of the AgGaSe2 crystal. By increasing the pump beam diameter from 1 to 3 mm (3-fold) and the pump energy from 6 to 54 mJ (9-fold), the idler pulse energy of 1.8 mJ (= 200 μJ × 9) will be obtained without increasing the pump intensity and without saturation of the output idler pulse energy.

[1]  Konstantin L. Vodopyanov,et al.  ZnGeP 2 optical parametric oscillator with 3.8–12.4-µm tunability , 2000 .

[2]  Manabu Watanabe,et al.  Bilirubin Calculi Crushing by Laser Irradiation at a Molecular Oscillating Region Wavelength Based on Infrared Absorption Spectrum Analysis Using a Free-Electron Laser: An Experimental Study , 2001, Surgery Today.

[3]  Kunio Awazu,et al.  Integrated ultraviolet and tunable mid-infrared laser source for analyses of proteins , 2007, SPIE LASE.

[4]  K. Awazu,et al.  LESS-INVASIVE LASER THERAPY AND DIAGNOSIS USING A TABLETOP MID-INFRARED TUNABLE LASER , 2010 .

[5]  K. Boller,et al.  High-efficiency mid-infrared ZnGeP2 optical parametric oscillator directly pumped by a lamp-pumped, Q-switched CrTmHo:YAG laser. , 2008, Optics letters.

[6]  K.-J. Boller,et al.  Mid-infrared ZGP optical parametric oscillator directly pumped by a lamp-pumped, Q-switched Cr,Tm,Ho:YAG laser. , 2007, SPIE LASE.

[7]  Konstantin L. Vodopyanov,et al.  Application of mid-infrared cavity-ringdown spectroscopy to trace explosives vapor detection using a broadly tunable (6–8 μm) optical parametric oscillator , 2002 .

[8]  M. Obara,et al.  Tunable mid-infrared, high-energy femtosecond laser source for glyco-protein structure analysis , 2007, LEOS 2006 - 19th Annual Meeting of the IEEE Lasers and Electro-Optics Society.

[9]  K. Awazu,et al.  An improvement of matrix-assisted laser desorption/ionization mass spectrometry using an infrared tunable free electron laser , 2004 .

[10]  Katsunori Ishii,et al.  Mid-infrared pulsed laser lithotripsy using an Er:YAG laser and a difference frequency generation laser , 2008, SPIE Photonics Europe.

[11]  Kunio Awazu,et al.  Mid-infrared tunable optical parametric oscillator pumped by a Q-switched Tm,Ho:YAG ceramic laser , 2009, LASE.

[12]  Robert L. Byer,et al.  Broadly tunable infrared parametric oscillator using AgGaSe2 , 1986 .

[13]  J. Drummond,et al.  High-resolution tunable mid-infrared spectrometer based on difference-frequency generation in AgGaS2. , 2004, Applied optics.

[14]  P B Phua,et al.  Coupled tandem optical parametric oscillator (OPO): an OPO within an OPO. , 1998, Optics letters.

[15]  K. Awazu,et al.  Selective removal of cholesterol esters in an arteriosclerotic region of blood vessels with a free‐electron laser , 1998, Lasers in surgery and medicine.

[16]  H. Hazama.  High-energy pulsed tunable mid-infrared laser aids biomedical applications , 2008 .

[17]  Hiromasa Ito,et al.  Generation of tunable mid-IR (5.5–9.3 μm) from a 2-μm pumped ZnGeP2 optical parametric oscillator , 2004 .

[18]  Konstantin L. Vodopyanov,et al.  AgGaS2 optical parametric oscillator continuously tunable from 3.9 to 11.3 μm , 1999 .

[19]  D. Nikogosyan,et al.  Nonlinear Optical Crystals: A Complete Survey , 2005 .

[20]  Hiromasa Ito,et al.  Generation of continuously tunable, 5–12 µm radiation by difference frequency mixing of output waves of a KTP optical parametric oscillator in a ZnGeP2 crystal , 2004 .

[21]  K. Awazu,et al.  Matrix-assisted laser desorption/ionization of protein samples containing a denaturant at high concentration using a mid-infrared free-electron laser (MIR-FEL) , 2005 .