Dynamic multimode analysis of Q-switched solid state laser cavities

Abstract

We derive a new model and simulation technique called "Dynamic Multimode Analysis (DMA)" to simulate the 3-dimensional dynamic behavior of a laser. A Gaussian mode analysis is used to obtain resonator eigenmodes taking into account thermal aberrations. These modes are coupled by a set of rate equations to describe the dynamic behavior of the individual modes for cw and Q-switched lasers. Our approach analyzes mode competition and provides a detailed description of the laser beam in terms of output power, beam quality factor M(2), and pulse shape. Comparison of experimental data with our simulation results provides new insight into the effect of mode competition and the operation of Q-switched lasers.

New approaches in teaching laser engineering classes: modeling and building up a laser

“…If the mirror reflectivity is assumed to be 99.5 %, which corresponds to 0.025 loss, the ASLD software predicts the output laser power of 1.1 W, consistent with the experimental results. The ASLD software ASLD uses the dynamic mode analysis for power computation [3].…”

Diode-pumped and passively Q-switched Er:YAG laser emitting at 1617 nm

“…To simulate a Q-switched cavity, a temporal resolution of the rate equations has to be done. The idea, already described in [7], is to monitor and refresh the total number of photons inside the cavity. With this value, one can know the photon density in the crystal volume to compute the new population inversions (spatially resolved) and the evolution of the photon number.…”

Numerical Analysis of Laser Diode Longitudinally Pumped Solid‐state Laser Generation Dynamics Using Traveling Wave Model

“…Therefore, two simplified methods are used for these purposes: Gaussian mode approach in combination with rate equations and beam propagation method based on the Huygens-Fresnel approximation of the diffraction theory [6]. Recently a new approach has been developed [34] in which the common set of rate equations is extended to a set of rate equation for the individual transverse modes being excited in the cavity. However, it should be noted that forward and backward traveling waves do not exist in these simplified methods.…”

“…However, it should be noted that forward and backward traveling waves do not exist in these simplified methods. For example, under assumption that mode shapes do not change in time, only energy density of the incoherent superposition of the individual modes is used in rate equations [34]. Thus, only the usage of TWM can provide the knowledge about intracavity dynamics during the pulse generation time.…”