Analysing the impact of non-parallelism in Fabry-Perot etalons through optical modelling

Dylan M. Marques*, James A. Guggenheim, Peter R.T. Munro

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

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Fabry-Perot (FP) etalons, composed of two parallel mirrors, are used widely as optical filters and sensors. In certain applications, however, such as when FP etalons with polymer cavities are used to detect ultrasound, the mirrors may not be perfectly parallel due to manufacturing limitations. As little is known about how the mirrors being non-parallel impacts upon FP etalon performance, it is challenging to optimize the design of such devices. To address this challenge, we developed a model of light propagation in non-parallel FP etalons. The model is valid for arbitrary monochromatic beams and calculates both the reflected and transmitted beams, assuming full-wave description of light. Wavelength resolved transmissivity simulations were computed to predict the effect that non-parallel mirrors have on the sensitivity, spectral bandwidth and peak transmissivity of FP etalons. Theoretical predictions show that the impact of the non-parallel mirrors increases with both mirror reflectivity and incident Gaussian beam waist. Guidelines regarding the maximum angle allowed between FP mirrors whilst maintaining the sensitivity and peak transmissivity of a parallel mirror FP etalon are provided as a function of mirror reflectivity, cavity thickness and Gaussian beam waist. This information, and the model, could be useful for guiding the design of FP etalons suffering a known degree of non-parallelism, for example, to optimize the sensitivity of polymer based FP ultrasound sensors.

Original languageEnglish
Pages (from-to)21603-21614
Number of pages12
JournalOptics Express
Issue number14
Early online date24 Jun 2021
Publication statusPublished - 5 Jul 2021

Bibliographical note

Publisher Copyright:
© 2021 Optical Society of America under the terms of the OSA Open Access Publishing Agreement

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics


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