# A Beam Propagation Method for Distorted Gaussian Beams

Pflaum C (2019)

**Publication Language:** English

**Publication Type:** Conference contribution, Conference Contribution

**Publication year:** 2019

**Publisher:** PAMM

**Conference Proceedings Title:** PAMM 2019

**Event location:** Wien

**URI:** https://onlinelibrary.wiley.com/doi/abs/10.1002/pamm.201900034

**DOI:** 10.1002/pamm.201900034

### Abstract

Distorted Gaussian beams arise in several applications in optics. One of
them is a laser amplifier. In a laser amplifier a Gaussian beam is
distorted by thermal lensing effects, polarization effects and gain
guiding. This leads to a decrease of the beam quality at the output of a
laser amplifier. An important question is how to calculate this
decrease of the beam quality and how to compute the amplified beam.
There exist several difficulties of existing simulation techniques for
the computation of optical beams. These are the high computational
amount in order to resolve the phase of the beam and modelling
non‐absorbing boundary conditions. We present a new beam propagation
method, which circumvents these difficulties. The idea is to decompose
the beam as a product of a Gaussian Beam TEM00 and an unknown distortion
function Ξ. This leads to an interesting partial differential equation
for Ξ, which contains a beam spreading convection term. This PDE is
solved numerically by finite elements and a Crank‐Nicolson space
stepping discretization. The resulting linear equation system is solved
by GMRES. The q‐parameter of the Gaussian beam is calculated in advance
by an ABCD matrix method. This leads to a highly efficient simulation
technique. It can be applied to simulate the amplification of Gaussian
beams in laser amplifiers.

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### How to cite

**APA:**

Pflaum, C. (2019). A Beam Propagation Method for Distorted Gaussian Beams. In *PAMM 2019*. Wien: PAMM.

**MLA:**

Pflaum, Christoph. "A Beam Propagation Method for Distorted Gaussian Beams." *Proceedings of the GAMM 2019, Wien* PAMM, 2019.

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