Broadband efficient second harmonic generation in media with a short-range order

The authors demonstrate broadband efficient quasiphase matched second harmonic generation (SHG) in nonlinear LiNbO3 crystals. The distribution of ferroelectric domains in a short-range order provides the possibility for broadband second harmonic generation in the visible range. This process is similar to the broadband SHG in random media, but it results in much higher conversion efficiency. The unique distribution of reciprocal vectors provided by the structural short-range order plays an important role in the enhancement. The achieved broadband SHG with high conversion efficiency will aid in the development of optics integration and multiple-channel devices. (c) 2007 American Institute of Physics.