Fig. 4: Effect of ML-TMD location on the parametric oscillations.

a Sketch of the parametric oscillator geometry with the ML-TMD placed at a distance d from the right mirror. b Incidence angle θ of the degenerate (Δω = 0) DRPOs as a function of the normalized distance d/L. The degenerate DRPOs are triggered by the same pump as above (λ₃ = 780 nm), and they occur at each d since, due to the physical coincidence of the signal and idler fields, the SR and IR conditions coincide and the PO condition is automatically satisfied (see Materials and methods). c Pump intensity threshold \({\it{I}}_{3Th}^{\left( i \right)}\) of the DRPOs reported in b as a function of d/L.