Tunable terahertz parametric oscillator synchronously-pumped by mode-locked picosecond Ti:Sapphire laser with MgO-doped LiNbO3

A terahertz (THz) parametric oscillator (TPO), which was based on the optical parametric process, in a doubly-resonant external enhancement cavity synchronously-pumped by a mode-locked picosecond Ti:sapphire laser with the center wavelength of 780 nm and the average output power of 850 mW, was built. Our TPO cavity including four mirrors and a 5 mol% MgO-doped LiNbO3 (MgO:LN) crystal with Si-prism couplers for the output coupling of the THz wave was designed so as to circulate both pump and idler waves in the same cavity simultaneously. Furthermore, we utilized a Hänsch-Couillaud method to stabilize the cavity. As a result, we developed an easily and continuously tunable picosecond TPO by changing the noncollinear phase-matching condition. The tunable wavelength range of the idler wave was from 782 to 787 nm, which corresponded to the THz frequency range from 1.0 to 3.4 THz according to the law of energy conservation. In addition, the measured angle between the pump and idler waves, which varied from 0.6 to 2.5 degrees, showed a good agreement with the theoretical calculation of the noncollinear phase-matching condition in all the above tuning range.

[1]  T. Hänsch,et al.  Laser frequency stabilization by polarization spectroscopy of a reflecting reference cavity , 1980 .

[2]  Kodo Kawase,et al.  Terahertz wave parametric source , 2002 .

[3]  David E. Zelmon,et al.  Infrared corrected Sellmeier coefficients for congruently grown lithium niobate and 5 mol. magnesium oxide doped lithium niobate , 1997 .

[4]  K. Kawase,et al.  Enhancement of terahertz-wave output from LiNbO(3) optical parametric oscillators by cryogenic cooling. , 1999, Optics letters.

[5]  四方 潤一.  Tunable terahertz-wave parametric oscillators using LiNbO3 and MgO:LiNbO3 crystals , 2000 .

[6]  H. Kumagai,et al.  Noncascading THz-wave parametric oscillator synchronously pumped by mode-locked picosecond Ti:sapphire laser in doubly-resonant external cavity , 2011 .

[7]  Kodo Kawase,et al.  Unidirectional radiation of widely tunable THz wave using a prism coupler under noncollinear phase matching condition , 1997 .

[8]  T Edwards,et al.  Compact source of continuously and widely-tunable terahertz radiation. , 2006, Optics express.

[9]  K. Kawase,et al.  Non-destructive terahertz imaging of illicit drugs using spectral fingerprints. , 2003, Optics express.

[10]  K. Kawase,et al.  Arrayed silicon prism coupler for a terahertz-wave parametric oscillator. , 2001, Applied optics.

[11]  Katalin Polgar,et al.  Temperature and composition dependence of the absorption and refraction of Mg-doped congruent and stoichiometric LiNbO3 in the THz range , 2005 .

[12]  Maya R. Gupta,et al.  Recent advances in terahertz imaging , 1999 .

[13]  P. Planken,et al.  Terahertz dielectric properties of polystyrene foam , 2002 .

[14]  F. Capasso,et al.  Terahertz Spectroscopy , 2010 .

[15]  Robert Osiander,et al.  Terahertz waves for communications and sensing , 2004 .