Compact and efficient Kerr-lens mode-locked diode-pumped actively Q-switched YVO4–Nd:YVO4 laser

New ducting model for analyzing the Gaussian beam propagation in nonlinear Kerr media and its application to spatial self-phase modulations

“…Equations ( 16) and (17) and their recasting as a nonlinear ABCD matrix have been successfully used in design and stability analysis of Kerr-lens mode-locked optical resonators [11][12][13][14][15]. Before plotting w(z) and R(z) for different z values, it would be useful to first determine the value of P c for the aforementioned experimental conditions.…”

“…As mentioned before, the nonphysical predictions of Magni's model near the self-focusing point and thereafter stem from the largeness of the P c value in equation ( 18) for the thermal optical nonlinearity that is dominant when a cw laser is used to observe the diffraction ring patterns. However, for designing Kerr-lens mode-locked optical resonators where the dominant nonlinearity is electronic in nature (n 2 ∼ 10 −16 cm 2 W −1 ) [8], this situation no longer holds and, as has been verified in practice by various groups [11][12][13][14][15], the model predictions are correct. Therefore, if our ducting model also produces the same results as Magni's model, when the electronic nonlinearity is used instead of the thermal one in our model formulation, its correctness can be verified.…”

“…Then, by numerically solving the obtained relations, results will be compared to the outcomes of one widely used model in this case. This model, which was developed by Magni et al [10], has a widespread use in designing Kerr-lens mode-locked optical resonators [11][12][13][14][15], where the electronic refractive nonlinearity is dominant inside the Kerr media. However, as will be shown in section 3, this model is deficient in properly describing Gaussian beam propagation in nonlinear Kerr media when the thermal nonlinearity prevails; one can use our proposed model for this case.…”

Compact and high repetition rate Kerr-lens mode-locked 532 nm Nd:YVO4laser

“…By choosing suitable pump beam size in crystal, enough nonlinear gain modulation will be produced for self-focusing. The δ parameter is described as the distribution of the Kerr nonlinear intensity in the cavity [14], as it measures the ability of the cavity to discriminate between the high-power (pulsed) and the low-power (continuous) regimes [22]. The larger the value of δ, the easier the KLM occurs and sustains.…”

“…Three order nonlinear Kerr effect (or intensity-dependent index of refraction) is a possible nonlinear interaction to lock the phases of the oscillating longitudinal modes. Kerr-lensinduced mode locking (KLM) in a Nd:YVO 4 laser has been demonstrated in recent years [13][14][15], with which a fast saturable absorber action with a simple mechanism can be achieved. In KLM, because of the gain bandwidth limits of Nd-doped vanadate crystal, the intensity-dependent index of refraction in the gain medium results in self-focusing of the ps pulses.…”