Isak Kilin Abstracts

Isak Kilen
  Ph.D. Candidate
  Applied Mathematics GIDP

  Photonics West-Physics & Simulation of Optoelectronic Devices XXIV
  San Francisco, CA
  February 13-18, 2016

Simulation and modeling of Ultrashort pulses in VECSELs

Authors: I. Kilen, J. Hader, S.W. Koch, J. Moloney

In mode locking of Vertical External Cavity Emitting Laser’s (VECSEL’s) with a saturable absorber, experiments have been able to generate light pulses on the order of 100fs. These ultrashort pulses are now on the same order as the characteristic timescale of the intraband scattering in the Quantum Wells (QW), and for modeling the mode locking behavior it is essential to understand the interaction of the light field with the QWs on a microscopic level. The challenge of using the microscopic theory is that there are significant computational requirements for mode locking simulations. The time scale of the light field propagating inside the cavity is on the order of nanoseconds while the interaction with the QWs is on the order of the length of the pulse.

I will talk about the modeling and numerical simulations of mode locking in VECSEL’s with a saturable absorbers inside a linear- and a V-cavity. The light field is propagated using Maxwell’s equations and the QW’s are modeled microscopically using the semiconductor Bloch equations. Studying the computationally intensive 2nd Born theory we can extract effective rates that are used to model the higher order correlation effects such as polarization dephasing. By investigating mode locking in this model we can extract useful information about how the microscopic carrier behavior influences the generation of mode locked pulses.

Abstract for Lay Audience

My work is focused on the design and numerical modeling of a particular type of laser cavity (VECSEL) and the accompanying microscopic dynamics. Current experiments are pushing laser pulse lengths further and further down and it is becoming vital to have numerical models that accurately describe the material interaction for these short pulses. By basing the design on solid understanding  of the underlying many particle physics, and simulations that show how the light field will interact with the active material, it is possible to optimize the cavity to take advantage of nonlinear behavior in the Quantum Well’s.

The modeling challenge is that there are a multitude of physical effects that require substantial computational resources. These range from simulation of the materials and their interaction with the light on the order of 100’s of femtoseconds, to the propagation in the cavity on the order of nanoseconds. In order to overcome these challenges parallel schemes have been used to speed up the simulations, clever models speed up the computationally intense microscopic dynamics while maintaining predictability.

The talk will be useful for the mode-­‐locking community in general as I will be presenting recent published results as well as advances into new domains of interest that make the current models interesting for a wider range of experiments.