Selective nucleation control in periodical poling for quasi-phase-matched wavelength converters

Summary form only given. In electric field poling, high voltage is applied to a ferroelectric crystal to reverse the polarization. Micro nuclei are generated and penetrate the crystal (nucleation), and then the domain walls move sidewise from the nucleation points (wall movement). Here we demonstrate a successful method to fabricate a periodically poled LiNbO/sub 3/ structure by separating nucleation and wall movement. In the nucleation process, high nucleation density is achieved by choosing the pulse width and pulse number. In the wall movement process, a uniform periodic structure is formed with flat domain walls. This technique can be applied to domain patterning in other ferroelectrics and could be a powerful solution to fabricating complicated domain structures such as short-period QPM devices and nano-scale nonlinear photonic crystals.