Details
| Original language | English |
|---|---|
| Qualification | Doctor rerum naturalium |
| Awarding Institution | |
| Supervised by |
|
| Date of Award | 12 Jul 2023 |
| Place of Publication | Hannover |
| Publication status | Published - 2023 |
Abstract
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Hannover, 2023. 128 p.
Research output: Thesis › Doctoral thesis
}
TY - BOOK
T1 - Nonlinear optics in thin film interference coatings
AU - Steinecke, Morten
PY - 2023
Y1 - 2023
N2 - Nonlinear optical effects play a crucial role in modern optical systems. They are applied in mode-locking for the generation of ultrashort optical pulses, in the generation of otherwise unavailable wavelengths, or for new approaches in measurement techniques. However, implementing the required nonlinear optical processes mainly relies on conventional optical systems comprising separate components and free-space constructions, which limits the possibilities for miniaturization and integration of functional groups. Contrary to this, optical interference coatings offer highly developed capabilities for combining optical functions into a single, monolithic stack of transparent materials. So far, the applications of optical coatings have generally been limited to the linear optical regime. If nonlinear effects were considered, it was mostly directed at their suppression to avoid undesired effects. This thesis, therefore, investigates the combination of selected nonlinear optical effects with specially designed optical coatings to create novel components as alternatives to established optical systems. Due to the amorphous nature of thin film coating materials, the two effects chosen for investigation are based on the third-order susceptibility χ(3). The first effect is the optical Kerr effect, which is utilized to achieve all-optical switching of incident light. In the second case, optical coatings are utilized to solve phase matching issues for the third harmonic generation in frequency tripling mirrors and significantly increase conversion efficiency. The manufacturing processes and material research are presented for both approaches, together with the experimental testing of the novel components’ function. It was found that while the frequency tripling mirrors provide a greatly enhanced efficiency compared to the third harmonic generated in more typical optical coatings, the total efficiency is currently limited by free-electron effects occurring during the conversion process. The optical switches show significant modulation of 20% in transmittance and 30% in reflectance with a repeatable process which can be clearly distinguished from laser-induced damage occurring at higher intensities. Therefore, the created optical switch can present a viable alternative to established switching concepts.
AB - Nonlinear optical effects play a crucial role in modern optical systems. They are applied in mode-locking for the generation of ultrashort optical pulses, in the generation of otherwise unavailable wavelengths, or for new approaches in measurement techniques. However, implementing the required nonlinear optical processes mainly relies on conventional optical systems comprising separate components and free-space constructions, which limits the possibilities for miniaturization and integration of functional groups. Contrary to this, optical interference coatings offer highly developed capabilities for combining optical functions into a single, monolithic stack of transparent materials. So far, the applications of optical coatings have generally been limited to the linear optical regime. If nonlinear effects were considered, it was mostly directed at their suppression to avoid undesired effects. This thesis, therefore, investigates the combination of selected nonlinear optical effects with specially designed optical coatings to create novel components as alternatives to established optical systems. Due to the amorphous nature of thin film coating materials, the two effects chosen for investigation are based on the third-order susceptibility χ(3). The first effect is the optical Kerr effect, which is utilized to achieve all-optical switching of incident light. In the second case, optical coatings are utilized to solve phase matching issues for the third harmonic generation in frequency tripling mirrors and significantly increase conversion efficiency. The manufacturing processes and material research are presented for both approaches, together with the experimental testing of the novel components’ function. It was found that while the frequency tripling mirrors provide a greatly enhanced efficiency compared to the third harmonic generated in more typical optical coatings, the total efficiency is currently limited by free-electron effects occurring during the conversion process. The optical switches show significant modulation of 20% in transmittance and 30% in reflectance with a repeatable process which can be clearly distinguished from laser-induced damage occurring at higher intensities. Therefore, the created optical switch can present a viable alternative to established switching concepts.
U2 - 10.15488/14149
DO - 10.15488/14149
M3 - Doctoral thesis
CY - Hannover
ER -