Nonlinear optical waveguides generated in lithium niobate by swift-ion irradiation at ultralow fluences.
A novel method to produce optical waveguides is demonstrated for lithium niobate (LiNbO(3)). It is based on electronic excitation damage by swift ions, i.e., with energies at approximately 1 MeV/amu or above. The new technique uses high-energy medium-mass ions, such as Cl, with electronic stopping powers above the threshold value for amorphization (5-6 keV/nm), reaching the maximum value a few micrometers inside the crystal. At the ultralow fluence regime (10(12)-10(13) cm(-2)) an effective nanostructured medium is obtained that behaves as an optical waveguide where light propagates transversally to the amorphous nanotracks created by every single impact. The method implies a reduction of 4 orders of magnitude with respect to He implantation. The optical waveguides present reasonable losses (~10 dB/cm) and significant second-harmonic generation (SHG) and electro-optic (EO) responses (>50% bulk) for the lowest fluences.
Olivares
J
J
1Instituto de Optica Daza de Valdés, CSIC, C/Serrano 121, 28006-Madrid, Spain. j.olivares@io.cfmac.csic.es
García-Navarro
A
A
García
G
G
Méndez
A
A
Agulló-López
F
F
García-Cabañes
A
A
Carrascosa
M
M
Caballero
O
O