Continuous-wave watt-level diamond Raman laser at 1634 nm by intracavity pumping with dual Nd:YVO₄ crystals

We demonstrated a watt-level continuous-wave intracavity diamond Raman laser operating at 1634 nm in the eye-safe spectral region. By employing a dual Nd:YVO₄ crystal pumping configuration in combination with a Z‑shaped cavity design, the thermal lensing effect in the laser crystal was significantly suppressed. Consequently, the maximum injected pump power was increased from 40 W in a single-crystal scheme to 130 W, yielding 18.4 W of fundamental laser at 1342 nm. With the fundamental beam tightly focused to a 65 μm waist radius on the diamond, continuous-wave Raman output at 1634 nm was achieved with a power of 1.46 W, representing the highest power reported. The device also exhibits good beam quality (M² < 1.3) and power stability (RMS < 2% over 1 hour). Numerical simulations further indicate that by increasing the local pump density within the Raman medium and optimizing the output coupling ratio, the output power can potentially be scaled to the 10 W level.