High-gain phosphate neodymium glass rod amplifiers with 60 mm diameter

Linear dependence of the time shift of an amplified pulseon the energy extraction from a laser amplifier

“…The measurements were performed for a symmetric bell-shaped 25-ns pulse and an asymmetric 10-ns pulse. One can see that the shift of the ampliéed pulse upon saturation is well described by linear dependence (15) and is independent of its shape.…”

“…However, even when this condition is considerably violated (E in G 0 % 300E s ), expression (14) gives the accuracy no worse than 10 %, which is quite sufécient for practical applications. Note that the error of expression (14) is much smaller than that of the expression proposed in [15] (see Fig. 4b).…”

“…One can see that in the case of weak saturation (E in G 0 5 E s ), the results of exact and approximate calculations coincide almost perfectly. However, even for a considerably stronger saturation (G 0 E in $ 150E s ), the error of expression (15) does not exceed 10 %. In practice, such accuracy is always sufécient.…”

“…Note that the factor kLgI in in (12) is equal to the B-integral in the absence of ampliécation, the érst fraction describes the well-known [15] correction for the B-integral in the case of unsaturated absorption, and the second fraction determines the change in the shape and the maximum value of B(t) due to saturation. By differentiating (12) with respect to time and equating the derivative to zero, we obtain for Gaussian pulse (6) in the weak saturation approximation (E in G 0 5 E s ) the approximate expressions for the shift Dt B of the B-integral maximum and its maximum value B max in the form…”

“…However, the authors either always use a rectangular pulse [1,2,13], which has no practical interest, or restrict themselves to the numerical analysis [14], which cannot give properties in the general case. The exclusion is papers [15] and [16], in which expressions are presented for estimating B max and calculating the duration of an ampliéed pulse and the duration of its leading edge. In this paper, we obtained analytically simple approximate expressions for all the quantities mentioned above in the weak saturation regime.…”