Highly Efficient Ultraviolet Harmonic Generation at a Nonlinear Crystal Interface

Abstract

High conversion efficiency is vital for the acquisition of UV light through nonlinear processes. Here, we investigate an alternative method to realize highly efficient second-harmonic generation (SHG) based on the interface of $\ensuremath{\beta}$ barium metaborate ($\ensuremath{\beta}\mathrm{BBO}$) and magnesium-doped lithium niobate ($\mathrm{MgO}$:LN). Theoretical simulations indicate that the SHG efficiency of our method is significantly higher than other phase-matching conditions. In the experiment, we demonstrate that higher conversion efficiency can be realized compared with only employing a single BBO crystal. Besides, the shortest output wavelength of SHG can reach 205 nm in our method. The method proposed here can open another way for the integrated ultraviolet laser and may promote the development of UV micromachining in the future.