Electro-optically Q-switched high-repetition-rate1.73 μm optical parametric oscillator

We demonstrate a potassium titanyl phosphate-based optical parametric oscillator(OPO) emitting at 1729 nm.A maximum output power of 1.56 W at 1729.4 nm is obtained with an original fundamental laser power of5.48 W. The pulse with a pulse duration of 11.22 ns exceeds 3 m J at a 500 Hz repetition rate. To our knowledge this is the highest energy output of an OPO laser emitting around 1.73 μm operating at a 100 Hz order of magnitude. This laser is primarily used for bond-selective imaging of deep tissue, a promising way for diagnosing vulnerable plaques in live patients.