Transverse-pumping approach for a powerful single-mode Ti:sapphire laser for near infrared lidar applications

We present a design of a transversely pumped and powerful Ti:sapphire laser, suitable for laser remote sensing in the near infrared (NIR) spectrum. Examining multiple pump configurations revealed that transversal pumping of Ti:sapphire crystals with a Nd:YAG laser (532 nm) from one or two sides yields maximum output power. Together with an optimized bow-tie resonator setup, we were able to extract up to 3 W (30 mJ, 100 Hz) of narrowband NIR laser emission from a cuboid 50 mm long Ti:sapphire crystal. Beam quality and divergence were determined as Mx2=1.1, My2=1.7, φ_x=0.5mrad, and φ_y=0.8mrad. The spectral purity (seeded, P≥170µW) was better than 99.8%. Additionally, we show a two-wavelength setup applicable to atmospheric water vapor lidar. The principle performance of this theory of operation suggests a good chance of scalability towards significantly enhanced power of future Ti:sapphire lasers.