We investigate the emission regimes of a room-temperature Er(1%):YLiF4 laser on the transition 4S3/2 - 4I15/2 using a model based on rate equations. The influence of the excited-state reabsorption losses and of the pump wavelength on the laser emission regime is discussed. Three pump wavelengths are investigated: 486 nm (direct pumping), 795 nm and 810 nm (both corresponding to upconversion pumping). The emission thresholds of the various regimes

Mathematical modeling is used to study the influence of pump wavelength on the emission of an Er(0.5 at.%):YAG laser on the transition 4S3/2 - 4I15/2 (561 nm). Three pump wavelengths (direct pumping: 488 nm, upconversion pumping: 800 and 810 nm) are investigated and the corresponding laser emission regimes are discussed. For upconversion pumping, we find an optimum pump wavelength and optimum resonator losses for lowering of the continuous-wave emission

Mathematical modeling is used to estimate the performances of the three-micron Er:YAG laser in various generation regimes. The model, based on simple rate equations, uses exclusively spectroscopic data and includes upconversion from both initial (4I11/2) and terminal (4I13/2) levels as well as the cross-relaxation from the pump level (4S3/2). Despite the unfavorable ratio between the lifetimes of the laser levels, the recirculation of the excitation

The efficiency of erbium three-micron laser (laser transition 4I11/2 - 4I13/2) depends essentially on the ratio of the parameters of active energy transfer upconversion (ETU) from the laser levels. The parameters of both ETU processes can be obtained from the analysis of the shape of the kinetics of the 4I11/2 level in concentrated Er:YAG crystals, under short pulse pumping. Mathematical modeling is used to evaluate the sensitivity of the method

The dynamical behavior of a green-emitting upconversion-pumped Er(0.5 at.%):YAG laser with reabsorption losses by an excited-state absorption process is studied. Stability analysis is used to identify the various regimes of laser emission and the bifurcations leading to them. The results are illustrated by Runge-Kutta integration of the rate equations. An analytical expression of the laser threshold is also presented. Calculated values of the laser

Mathematical modeling, based on rate equations, is used to estimate the theoretical limit of the emission efficiency of 3-um Er:YAG laser (laser transition 4I11/2 - 4I13/2) in both continuous wave (CW) and free-generation regimes. This model exclusively uses spectroscopic data and includes upconversion from both initial and terminal laser levels as well as the cross-relaxation from the "pump level" 4S3/2. The recirculation of the excitation on the

In this paper we discuss the up-conversion processes responsible for violet luminescence from the high energy erbium levels 2P3/2 (located at ~31000 cm-1) and 2H9/2 (~24000 cm-1) as well as for green luminescence from 4S3/2 level (~18000 cm-1) in low-concentrated (0.1 at.%) Er:YAG crystals, at room temperature, excited with a cw Ti:Sapphire laser (pump transition 4I15/2 - 4I9/2). At this concentration excited state absorption (ESA) is the dominant