Green light waveguide demonstration on Y b:Nb:RbTiOPO4/RbTiOPO4 epitaxial layers

In this paper epitaxial layers of RbTiOPO4 doped with Y b3+ on substrates of RbTiOPO4 have been grown by Liquid Phase epitaxy on the (001) plane, which contains the phase matching direction for Type II Second Harmonic Generation for the Y b3+ emission wavelength range. These layers can guide polarized light parallel to the c crystallographic direction. A 5 μm-thickness epitaxial layer can guide 3 propagation modes as it has been observed by the dark-mode spectrum. The sample was polished in both end-faces to visualize the TM modes of the waveguides. The near field pattern was recorded by a CCD camera, using a green diode laser at a wavelength of 532 nm, coupled into, and out from the waveguide using two microscope objectives. The demonstration of good guiding at a wavelength of 532 nm in Y b:Nb:RbTiOPO4 waveguides is one of the important steps to obtain Self Frequency Doubling laser waveguides.