Resumen

VALLESPI, Arturo; SLEZAK, Verónica B  y  PEURIOT, Alejandro L. Optical parametric oscillator prototype with PPLN crystal. An. AFA [online]. 2016, vol.27, n.3, pp.100-108. ISSN 0327-358X.

An optical parametric oscillator (OPO) was designed and built using a 4 cm long and 1 mm thick nonlinear crystal (NLC) MgO 5% LiNbO₃(Covesion) pumped with a pulsed Nd: YVO₄ (1064 nm 7 W at 10 kHz, Coherent-Matrix-1064-7-10). The NLC consists of five periodically poled gratings with alternating polarization in the ferroelectric domains, in order to compensate the phase difference; it is called PPLN (Periodically Poled Lithium Niobate). The NLC is contained in a cavity of two mirrors: in this case the resonator feeds back a single wave (signal or idler). The crystal is confined in an oven in order to achieve the OPO's emission tuning by varying the temperature and the period of the network. The crystal has 5 gratings (1x1 mm section of the grating) and covers a region of the mid-IR from 1,48 to 2,12 µm (signal) and from 2,13 to 3,78 µm (idler). The cavity is formed by a 0,5 m focus silver layer mirror and a dielectric plane mirror reflecting the signal (~98%). The pump peak intensity focused on the crystal is ~ 29 MW/cm² at 1 kHz (30 ns pulse width) and is considered as a TEMoo beam. In the first experiments, the range of emission threshold, the temporal shape of the pulses, the energy conversion efficiency, sensitivity and stability of the cavity were determined by varying the temperature.

Palabras clave : Optical parametric oscillator; Nonlinear crystal; Cavity; Frequency conversion; PPLN.

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