Effect of gain anisotropy on low-frequency dynamics in four-level solid-state lasers

Abstract

Our anisotropic rate equation model outlines the relationship between the relaxation dynamics in a four-level solid-state laser and its anisotropic gain properties. Anisotropic pump rates and stimulated emission cross-sections were included to account for specific atom orientations in the gain material. The model is compared with experimental measurements of two relaxation oscillation frequencies which are related to the anisotropic atom-laser interaction in orthogonally polarized dual-mode lasers. The model predicts that crystal orientation and pump polarization affect the laser operation characteristics, as found experimentally. The gain anisotropy influences the fast laser dynamics, as in single-mode relaxation oscillations.

Mode locking of Yb:GdYAG ceramic lasers with an isotropic cavity

“…However, because the pulses share the same laser gain, there is gain competition between them. As a result of the cooperative interaction the pulse intensity variation exhibited antiphase dynamics [13][14][15][16][17]. The antiphase dynamics is on the time scale of the gain recovery time, which is far slower than the mode locked pulse width and the cavity roundtrip time of the laser.…”

3D Imaging Based on Depth Measurement Technologies

“…The essential equivalence of light wavefront and ray field allows the interchangeable compatibility between them. Hologram synthesis from light ray field [ 66 , 206 , 207 ] gets benefits from this fact. This lets holographic imaging enable a breakthrough for the interferometric requirement, and makes a hologram of the real world more practical.…”

“…Except holographic stereogram [ 181 ] and synthesizing hologram from the light ray field [ 66 , 179 , 206 , 207 ], obtaining the hologram from depth measurements has also been proved possible. Not surprisingly, it has been proven that a Fourier hologram can be synthesized directly from depth measured photographic images with [ 53 , 54 ] where is the coordinate of the Fourier spectrum plane, is the number of depth measurements, and is the depth interval between two adjacent measurements.…”

“…As the issues in light ray reconstruction from depth measurements, the hologram synthesis shows the same problem, which needs further investigation. These kinds of issues also happen in the hologram synthesis from a light ray field [ 43 , 206 ].…”

An FDTD algorithm for simulating light propagation in anisotropic dynamic gain media

“…The problem of anisotropic gain is common in lasers due to crystal orientation. This case is found in solid-state lasers, due to the difficulty of having perfect pumping alignment [1], and in semiconductor lasers, especially vertical cavity surface-emitting laser (VCSEL) [2]. For edge emitting lasers (EELs), the gain is high and the anisotropy is neglected.…”