Ultraviolet generation at 266 nm in a novel organic nonlinear optical crystal: l -pyrrolidone-2-carboxylic acid

A novel organic nonlinear optical crystal, l-pyrrolidone-2-carboxylic acid (l-PCA), has been found to be phase matchable for second-harmonic generation (SHG) and sum-frequency mixing down to the UV range at room temperature. Tunable radiation down to 266 nm was obtained. The nonlinear coefficient d14 of l-PCA for the fundamental wavelength of 532 nm was determined to be 0.32 pm/V. The angular acceptance (the full width at half-maximum) of the type II phase-matched SHG has also been measured to be 3.03 mrad cm which agreed with the calculated value. This value is much larger than that of the type I phase-matched SHG in β-BBO.