Fabrication of SPE Waveguides on PPLN: Formation of Nanodomains and Their Impact on the SHG Efficiency

Abstract

In this paper, we present the material characterization that has been made to explain the poor nonlinear performance observed in certain channel waveguides produced by soft proton exchange in periodically poled congruent lithium niobate (PPLN) crystals. The study was performed using complementary methods of domain visualization: piezoelectric force microscopy and confocal Raman microscopy. It has been shown that the waveguide fabrication process can induce the formation of the structure of needle like nanodomains, which can be responsible for the degradation of the nonlinear response of the waveguides created in PPLN crystals.

Keywords:

• Soft proton exchange
• periodical poling
• nanodomain structure
• second harmonic generation

Acknowledgments

The equipment of the Ural Center for Shared Use “Modern nanotechnology” UrFU was used for PFM and CRM measurements.

Funding

The research was made possible in part by the Ministry of Education and Science of the Russian Federation (contract No. 14.594.21.0011); RFBR and the Government of Sverdlovsk region (Grant 13-02-96041-r-Ural-а); by RFBR (Grants 13-02-01391-a, 14-02-01160-a, 14-02-90447 Ukr-a) and by the financial support for young scientists provided by the Ural Federal University development program and the French program for joint supervision of PhD thesis.