### Abstract

This tutorial gives an overview of the microscopic approach developed to describe equilibrium and nonequilibrium effects in optically excited semiconductor systems with an emphasis to the application for VECSEL modelling. It is outlined how nonequilibrium quantum theory is used to derive dynamic equations for the relevant physical quantities, i.e. The optically induced polarization and the dynamical carrier occupation probabilities. Due to the Coulombic many-body interactions, polarization and populations couple to expectation values of higher-order quantum correlations. With the help of a systematic correlation expansion and truncation approach, we arrive at a closed set of equations. Formally these can be combined with Maxwell's equations for the classical light field, yielding the Maxwell-semiconductor Bloch equations (MSBE). However, instead of the more traditional approach where losses and dissipative processes are treated phenomenologically and/or through coupling to external reservoirs, we derive fully microscopic equations for the carrier-carrier and carrier-phonon scattering as well as the effective polarization dephasing. Due to their general nature, the resulting equations are fully valid under most experimentally relevant conditions. The theory is applied to model the high-intensity light field in the VECSEL cavity coupled to the dynamics of the optical polarization and the nonequilibrium carrier distributions in the quantum-well gain medium.

Original language | English (US) |
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Title of host publication | Proceedings of SPIE - The International Society for Optical Engineering |

Publisher | SPIE |

Volume | 8966 |

ISBN (Print) | 9780819498793 |

DOIs | |

State | Published - 2014 |

Event | Vertical External Cavity Surface Emitting Lasers (VECSELs) IV - San Francisco, CA, United States Duration: Feb 2 2014 → Feb 4 2014 |

### Other

Other | Vertical External Cavity Surface Emitting Lasers (VECSELs) IV |
---|---|

Country | United States |

City | San Francisco, CA |

Period | 2/2/14 → 2/4/14 |

### Fingerprint

### Keywords

- High power operation
- Microscopic theory
- Nonequilibrium effects
- Short pulseoperation
- VECSEL modelling

### ASJC Scopus subject areas

- Applied Mathematics
- Computer Science Applications
- Electrical and Electronic Engineering
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics

### Cite this

*Proceedings of SPIE - The International Society for Optical Engineering*(Vol. 8966). [896603] SPIE. https://doi.org/10.1117/12.2036083

**Microscopic VECSEL modeling.** / Koch, Stephan W; Hader, Jorg; Moloney, Jerome V.

Research output: Chapter in Book/Report/Conference proceeding › Conference contribution

*Proceedings of SPIE - The International Society for Optical Engineering.*vol. 8966, 896603, SPIE, Vertical External Cavity Surface Emitting Lasers (VECSELs) IV, San Francisco, CA, United States, 2/2/14. https://doi.org/10.1117/12.2036083

}

TY - GEN

T1 - Microscopic VECSEL modeling

AU - Koch, Stephan W

AU - Hader, Jorg

AU - Moloney, Jerome V

PY - 2014

Y1 - 2014

N2 - This tutorial gives an overview of the microscopic approach developed to describe equilibrium and nonequilibrium effects in optically excited semiconductor systems with an emphasis to the application for VECSEL modelling. It is outlined how nonequilibrium quantum theory is used to derive dynamic equations for the relevant physical quantities, i.e. The optically induced polarization and the dynamical carrier occupation probabilities. Due to the Coulombic many-body interactions, polarization and populations couple to expectation values of higher-order quantum correlations. With the help of a systematic correlation expansion and truncation approach, we arrive at a closed set of equations. Formally these can be combined with Maxwell's equations for the classical light field, yielding the Maxwell-semiconductor Bloch equations (MSBE). However, instead of the more traditional approach where losses and dissipative processes are treated phenomenologically and/or through coupling to external reservoirs, we derive fully microscopic equations for the carrier-carrier and carrier-phonon scattering as well as the effective polarization dephasing. Due to their general nature, the resulting equations are fully valid under most experimentally relevant conditions. The theory is applied to model the high-intensity light field in the VECSEL cavity coupled to the dynamics of the optical polarization and the nonequilibrium carrier distributions in the quantum-well gain medium.

AB - This tutorial gives an overview of the microscopic approach developed to describe equilibrium and nonequilibrium effects in optically excited semiconductor systems with an emphasis to the application for VECSEL modelling. It is outlined how nonequilibrium quantum theory is used to derive dynamic equations for the relevant physical quantities, i.e. The optically induced polarization and the dynamical carrier occupation probabilities. Due to the Coulombic many-body interactions, polarization and populations couple to expectation values of higher-order quantum correlations. With the help of a systematic correlation expansion and truncation approach, we arrive at a closed set of equations. Formally these can be combined with Maxwell's equations for the classical light field, yielding the Maxwell-semiconductor Bloch equations (MSBE). However, instead of the more traditional approach where losses and dissipative processes are treated phenomenologically and/or through coupling to external reservoirs, we derive fully microscopic equations for the carrier-carrier and carrier-phonon scattering as well as the effective polarization dephasing. Due to their general nature, the resulting equations are fully valid under most experimentally relevant conditions. The theory is applied to model the high-intensity light field in the VECSEL cavity coupled to the dynamics of the optical polarization and the nonequilibrium carrier distributions in the quantum-well gain medium.

KW - High power operation

KW - Microscopic theory

KW - Nonequilibrium effects

KW - Short pulseoperation

KW - VECSEL modelling

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U2 - 10.1117/12.2036083

DO - 10.1117/12.2036083

M3 - Conference contribution

SN - 9780819498793

VL - 8966

BT - Proceedings of SPIE - The International Society for Optical Engineering

PB - SPIE

ER -