Acousto-optic tunable second harmonic generation in periodically poled LiNbO_3

Zi-Yan Yu,Fei Leng,Yan-Qing Lu,Xiang-Fei Chen,Xiao-Shi Qian,Fei Xu

doi:10.1364/oe.17.011965

Abstract

Acousto-optic (AO) tunable second harmonic generation (SHG) was proposed in periodically poled lithium niobate (PPLN). The acoustic wave could either be induced from an external transducer or self-generated in PPLN driving with a cross-field radio frequency field. The reciprocal vector of PPLN compensates the SHG wave-vector mismatch when quasi-phase- matching (QPM) condition is satisfied, while phonons with suitable frequencies may affect it by scattering photons to different polarization state. The QPM SHG and AO polarization rotation are coupled together. Second harmonic waves' intensities, polarization states and even phases thus could be manipulated instantly through AO interaction.

Highlights

Wavelength scale artificial photonic microstructures have been hot topics in the past two decades [1, 2]
As QPM has a lot of advantages over the birefringence phase matching, studying the AO QPM nonlinear effects would have both fundamental interest in Physics and important technical applications
We found that the acoustic wave could affect the wave vector matching between fundamental wave (FW) and its second harmonic (SH)

Summary

Introduction

Wavelength scale artificial photonic microstructures have been hot topics in the past two decades [1, 2]. The quantum description reveals that photons exhibit similar characteristics like electrons. Concepts such as Brillouin zone, band gap could be introduced to photonic crystals. Considering the similarity to PCs, QPM materials have been named nonlinear photonic crystals as well [5, 6]. It would be interesting to see how the photon-phonon interacts in nonlinear PCs, i.e., artificial QPM microstructures. As QPM has a lot of advantages over the birefringence phase matching, studying the AO QPM nonlinear effects would have both fundamental interest in Physics and important technical applications. We studied the photon-phonon interaction in a typical QPM material, the periodically poled LiNbO3 (PPLN).

Theory and simulation

Findings

Conclusion