Cavity decay rate and relaxation oscillation frequency in unconventional laser cavities

Modeling a Passively Q-Switched Nd:YVO4 Laser with an Application to Spatio-Temporal Instability

“…The rate equation describes the propagation of the optical field E g;n through the gain medium that is lumped into a single sheet, where the index n is the number of iterations. According to other studies, 13,15,16) the optical field and the total atomic population in the excited state, N g , are given by…”

“…When the transverse effect is to be considered, an iterative method based on the Fox-Li approach 12) can be adopted to determine the transverse field distribution in a laser system. [13][14][15][16] Such an iterative model is established by combining the rate equation and the generalized Huygens diffraction integral. Since the standing wave cavity configuration can be unfolded into an equivalent lens guide system, the laser can be characterized by a cascading propagation of the optical field in the optical medium and the cold cavity.…”

“…Since the standing wave cavity configuration can be unfolded into an equivalent lens guide system, the laser can be characterized by a cascading propagation of the optical field in the optical medium and the cold cavity. This laser model has been applied to determine the cavity decay rate in the linear regime 13) and the instability, 15,16) depending on the cavity configuration in cw solid-state lasers. To examine the transverse field distribution in a passively Q-switched laser, the space-dependent rate equation, associated with a saturable absorber, is added to the laser model.…”

“…The generalized Huygens diffraction integral with the roundtrip ABCD matrix specifies the propagation of the optical field in the cold cavity. 13,15,16) The optical field is as follows…”

Determining the average path length of amplified spontaneous emission in a four-level laser near the 1/3 mode-degeneracy cavity configurations

“…where Δt is the round-trip time, m and m + 1 are the mth and the (m + 1)th round trips for the propagating (lasing) electric field E m through the gain medium, E 2 s ¼ 2h=" 0 s is the saturation parameter of the active medium, 15,16) λ is the wavelength of the laser, σ is the cross section for stimulated emission, h is Planck's constant, and ε 0 is the vacuum permittivity. Note that N 2 was assumed to be independent of position in Ref.…”