Multi-resonant optical parametric oscillator based on 2D-PPLT nonlinear photonic crystals
Mohamed LAZOUL, Khadidja LADOUR, Lotfy Mokhtar SIMOHAMED
École Militaire Polytechnique Bordj El Bahri, Algeria
Azzedine BOUDRIOUA Université de Paris
France
Lung-Han PENG National Taiwan University
Taiwan
Abstract- The aim behind this work is to achieve a multiresonant optical parametric oscillator based on two dimensional periodically poled crystals, designed to allow multiple wavelength generation. Two dimensional nonlinear photonic crystals are characterized by multiple reciprocal lattice vectors contribution to the quasi-phase matching scheme. We are particularly interested by the multi-wavelength parametric generation to achieve a multi-resonance optical parametric oscillator. The performances the optical parametric oscillator are studied in terms of generation efficiency and multi-wavelength generation.
Keywords - Optical parametric oscillator, 2D-PPLT, multiresonant OPO.
An optical parametric oscillator (OPO) is the last step towards an efficient and highly flexible laser source. An OPO emits a tunable coherent light as long as the parametric gain compensates the energy losses when the oscillation threshold is reached. Their high efficiency and wide tuning range, which is only limited by the transparency range of the nonlinear crystal, allowed the OPOs to become highly attractive all-solid laser sources for various applications. In the case of two- dimensional nonlinear photonic crystals (2D-NLPC) [1] many lattice vectors can be involved in different quasi phase matching schemes which are in the origin of multiple nonlinear processes. Theoretical and experimental studies [2, 3] reported a possible gain enhancement of optical parametric oscillation in 2D-NLPC that can be reached through the contribution of multiple lattice vectors to phase-match the same nonlinear process.
The aim behind this work is to achieve an optical parametric oscillator based on 2D periodically poled lithium tantalate crystals (2D-PPLT) designed to allow multiple reciprocal lattice vectors contribution to the quasi-phase matching scheme [3]. We are particularly interested by the multi-wavelength parametric generation performed by the 2DPPLT crystals to achieve a multi-resonant optical parametric oscillator. The experimental setup of the proposed nanosecond multi-resonant OPO is shown in Fig.1-a. The crystal reciprocal lattice is characterized by circular poled regions distributed according to a square lattice with a grating period Λx=Λy= 8.52 μm. The performances of 2D-PPLT based OPO are studied in terms of generation efficiency and multi-wavelength generation.
We recorded the idler spectrum, as shown in Fig 1-b, just near the oscillation threshold. It consists of several peaks due to the multi-wavelength nature of the parametric generation performed by the 2D-PPLT crystal. By increasing the pump power, we observe that the spectrum is characterized by a single peak. All the other peaks, previously observed, are not amplified in the same way. We can explain this behavior by a competition between different interactions coupled inside the photonic crystal.
REFERENCES
[1] V. Berger, “Nonlinear photonic crystals,” Phys. Rev. Lett. 81, pp. 4136- 4139, 1998.
[2] H.-C. Liu, and A. H. Kung, “Substantial gain enhancement for optical parametric amplification and oscillation in two-dimensional χ(2) nonlinear photonic crystals,” Opt. Exp. 16, pp. 9714-9725, 2008.
[3] M. Lazoul, A. Boudrioua, L. M. Simohamed, A. Fischer and L-H Peng,
“Experimental study of multiwavelength parametric generation in a twodimensional periodically poled lithium tantalate crystal,” Opt. Lett.
38(19), pp 3892-3894, 2013.
Fig. 1. (a) Experimental setup of 2D-PPLT based OPO (b) Generated spectrum for a pump power near the oscillation threshold