Three-Photon Resonant Third Harmonic Generation of H₂ in Vacuum Ultraviolet and Extreme Ultraviolet Regions

Tunable coherent vacuum ultraviolet and extreme ultraviolet radiation have been produced in H₂ by three-photon resonant third harmonic generation via B¹ Σ⁺_u(v’) ← X¹ Σ⁺_g (v = 0 ) and C¹ II_u(v’) ← X¹ Σ⁺_g ( v = 0 ) transitions. Highly resolved third harmonic spectrum exhibits some distinct characteristics. Phase-matching effect of the nonlinear optical process is also discussed.