arXiv subjects

Vladislav V. Dudelev

Publications and source records attributed to Vladislav V. Dudelev.

3 recordsLinked to original sources

arXiv2024

An effect of a pump pulse rising edge on the QCL build-up time: the analytical approach

In this work, we provide a simplified theoretical analytical estimation of the quantum cascade laser build-up time, accurately taking into account the main effects: the QCL overheating during the pump pulse and the photon mode filling effect. The non-trivial interplay of the mentioned effects brings about a variety of possible experimental build-up time behaviors. The latter range from decreasing curvature for low-power devices to non-monotonous function for devices performing at high power.

physics.optics↗

arXiv2023

QCL active region overheat in pulsed mode: effects of non-equilibrium heat dissipation on laser performance

Quantum cascade lasers are of high interest in the scientific community due to unique applications utilizing the emission in mid-IR range. The possible designs of QCL are quite limited and require careful engineering to overcome some crucial disadvantages. One of them is an active region (ARn) overheat, that significantly affects the laser characteristics in the pulsed operation mode. In this work we consider the effects related to the non-equilibrium temperature distribution, when thermal resistance formalism is irrelevant. We employ the heat equation and discuss the possible limitations and structural features stemming from the chemical composition of the AR. We show that the presence of alloys in the ARn structure fundamentally limits the heat dissipation in pulsed and CW regimes due to their low thermal conductivity. Also the QCL post-growths affects the thermal properties of a device only in (near)CW mode while it is absolutely invaluable in the pulsed mode

cond-mat.mes-hall↗

arXiv2023

QCL dynamics: thermal effects and rate equations beyond mean-field approach

The correct accounting for thermal effects is always a challenge when one needs to make quantitative predictions for any laser applications. In such complicated devices as quantum cascade lasers temperature strongly affects the operational conditions preventing reaching the CW mode as well as efficient lasing in pulsed regime. Rate equations are the most effective and simple way to model laser dynamics. However, the conventional approaches operate under the mean-field approximation, considering finite number of population levels, generalizing the obtained results to the infinite number of cascades, and do not take heating into account. In this work we modify the conventional three-level rate equation approach by adding self-heating description and applying it to the calculation of QCL dynamics. As a result we show how temperature affects the threshold characteristics and build-up time and include electronic aspects to the description of QCL.

cond-mat.mes-hall↗