Intrinsic second harmonic generation from unpoled doped silica multilayered thin films
Second harmonic light generation (SHG) was observed from as-deposited silica glass thin films suitable for waveguiding, without the need for an inversion symmetrybreaking poling treatment. Thin film stacks of up to 16 layers of alternating 2% phosphorusdoped and undoped silica glass on silica substrates were prepared and probed with a pulsed Nd:YAG laser at 1064 nm. We observed that even though these structures were not poled, they possess a net second order non-linearity with a value of the order of 0.03 pm/V. The SHG increased with the number of layers (total thicknesses between 4 and 9.6 μm have been tested) and also depended on the thickness ratio between the doped and undoped layers. Annealing at 800°C for 4 hours removed the nonlinearity completely.
|Journal||Optical Materials Express|
Jafari, S.H. (Seyed Hamed), Novoa Lopez, J.A. (Jose Antonio), Haque, T. (Tahseen), Albert, J, & Smelser, C. (2017). Intrinsic second harmonic generation from unpoled doped silica multilayered thin films. Optical Materials Express, 8(1), 1–11. doi:10.1364/OME.8.000001