We report on backward second-harmonic-generation in bulk periodically poled congruent lithium niobate with a 3.2 micron period. A tunable continuous-wave Ti:sapphire laser allowed us exciting two resonant quasi-phase-matching orders in the backward configuration. The resonances were also resolved by temperature tuning and interpolated with standard theory to extract relevant information on the sample.
Stivala, S., Busacca, A., Curcio, L., Oliveri, R.L., Riva Sanseverino, S., Assanto, G. (2010). Continuous-wave backward frequency doubling in periodically poled lithium niobate. APPLIED PHYSICS LETTERS, 96, 111110-1-111110-3.