Optical losses of sputtered Ta2O5 films

Duparré, Angela; Welsch, E.; Walther, H. G.; Kühn, Hans-Joachim; Schirmer, G.

doi:10.1051/jphys:019870048070115500

Cited by 12 publications

(2 citation statements)

References 6 publications

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“…Kita considered L to be ~100nm [14] and Schmid's measured value is 180nm, with which a good experimental and analytical agreement is achieved [25]. For deposited Ta 2 O 5 thin film, the measured correlation length are ranging from ~100nm [37], 400nm [38] and 49 to 282nm [39]. Due to the rather wide range of the correlation length reported, the relationship between scattering loss and correlation length is first investigated by calculating the loss of fundamental modes as a function of correlation length and core thickness using Eqns.…”

Section: Modal Field Coupling Efficiency and Scattering Loss Calculat...mentioning

confidence: 95%

Effect of Scattering Loss on Optimization of Waveguide Enhanced Raman Spectroscopy

Liu,

Ettabib,

Wilkinson

et al. 2024

J. Lightwave Technol.

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Waveguide enhanced Raman spectroscopy (WERS) is a promising sensing technology requiring accurate waveguide optimization to increase the pump/signal surface intensity. Traditionally, WERS has been focused on single-mode operation, which results in stringent waveguide parameter control and increased propagation losses. In this work, we have studied theoretically and experimentally the impact of planar waveguide thickness on surface scattering losses and the waveguide propagation losses. In our study, we consider radiation from a Raman-emitting dipole on a waveguide can be captured back into the waveguide in polarization and spatial modes different from the pump mode, provided the waveguide can support them. In the case of randomly-distributed dipoles, we consider the Raman gain coefficients corresponding to all possible combinations of pump and signal polarization and spatial modes. We have introduced a new generalized FOM to optimize planar waveguidebased WERS sensors under multimode excitation/collection operation and waveguidethickness-and mode-dependent propagation losses. The FOM is shown to increase with the mode order as a result of the combination of substantial reduction in propagation loss, increased number of collecting modes, longer optimum sensing lengths, and this occurs despite the concomitant surface intensity reduction. This implies that in the case of randomly distributed dipoles, the single-mode pump excitation is not strictly required, and multimode pump excitation will give superior conversion efficiencies.

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Section: Modal Field Coupling Efficiency and Scattering Loss Calculat...mentioning

confidence: 95%

Effect of Scattering Loss on Optimization of Waveguide Enhanced Raman Spectroscopy

Liu,

Ettabib,

Wilkinson

et al. 2024

J. Lightwave Technol.

View full text Add to dashboard Cite

show abstract

“…Kita considered L to be ~100nm [14] and Schmid's measured value is 180nm, with which a good experimental and analytical agreement is achieved [25]. For deposited Ta2O5 thin film, the measured correlation length are ranging from ~100nm [37], 400nm [38] and 49 to 282nm [39]. Due to the rather wide range of the correlation length reported, the relationship between scattering loss and correlation length is first investigated by calculating the loss of fundamental modes as a function of correlation length and core thickness using Eqns.…”

Section: Modal Field Coupling Efficiency and Scattering Loss Calculat...mentioning

confidence: 95%

Effect of scattering loss on optimization of waveguide enhanced Raman spectroscopy

Liu¹,

Ettabib²,

Wilkinson³

et al. 2023

Preprint

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Waveguide enhanced Raman spectroscopy (WERS) is a promising sensing technology requiring accurate waveguide optimization to increase the pump/signal surface intensity. Traditionally, WERS has been focused on single-mode operation, which results in stringent waveguide parameter control and increased propagation losses. In this work, we have studied theoretically and experimentally the impact of planar waveguide thickness on surface scattering losses and the waveguide propagation losses. In our study, we consider radiation from a Raman-emitting dipole on a waveguide can be captured back into the waveguide in polarization and spatial modes different from the pump mode, provided the waveguide can support them. In the case of randomly-distributed dipoles, we consider the Raman gain coefficients corresponding to all possible combinations of pump and signal polarization and spatial modes. We have introduced a new generalized FOM to optimize planar waveguide-based WERS sensors under multimode excitation/collection operation and waveguide-thickness- and mode-dependent propagation losses. The FOM is shown to increase with the mode order as a result of the combination of substantial reduction in propagation loss, increased number of collecting modes, longer optimum sensing lengths, and this occurs despite the concomitant surface intensity reduction. This implies that in the case of randomly distributed dipoles, the single-mode pump excitation is not strictly required, and multimode pump excitation will give superior conversion efficiencies.

show abstract