Search results for "Lery"

Analysis of whispering gallery modes resonators: wave propagation and energy balance models

2021

Electromagnetic whispering gallery modes (WGM) are surface waves guided by the curvature of an interface. Microspheres, microdisks and microcylinders –as for example standard optical fibers– are high quality microresonators for the WGM. In fact, they can be regarded as compact and small ring resonators. Here, we present a comparison between wave propagation and energy balance models, stablishing the equivalence and discussing the basic characteristics of these two complementary approaches.

Refractive index sensor based on whispering gallery modes resonances of thin capillaries

2007

PhoXonic Whispering Gallery Mode Resonators: parametrical optomechanic oscillations and its applications

2021

We report on the experimental analysis of parametrical optomechanical oscillations and photo-acoustical applications such as flow cytometers in hollow phoxonic whispering gallery mode resonators. Both phenomena can be enchanced or suppressed and showed chaotic behavior.

Interrogation of whispering-gallery modes resonances in cylindrical microcavities by backreflection detection

2009

The excitation of whispering-gallery-mode resonances of cylindrical microcavities, using narrow fiber tapers, produces simultaneously the excitation of spiral modes. The power coupled to the spiral modes leads to a significant broadening of the dips observed in the spectrum of light transmitted through the taper. We demonstrate that whispering-gallery modes resonances of cylindrical microcavities can also be interrogated by measuring the reflection spectrum. Unlike the dips observed in transmission, the peaks in the reflection spectrum are symmetric and narrower than the corresponding transmission dips.

Analytical description of resonances in Fabry–Perot and whispering gallery mode resonators

2021

Whispering gallery mode optical resonators have attracted attention due to their simplicity and applicability for sensing. In this paper, analytical formulas are provided that describe resonance conditions in optical resonators. Basic terms (resonance wavelengths and frequencies, free spectral range, Q -factor, summation principle of Q -factors of various processes, finesse, etc.) are introduced. A description of interference of an infinite number of waves of progressively smaller amplitudes and equal phase differences is given. A description of a Fabry–Perot resonator with nonequal reflection coefficients is also given as well as analysis of all-pass and add-drop optical filters. The prese…

Comparative analysis of spectral coherence in microresonator frequency combs

2014

Microresonator combs exploit parametric oscillation and nonlinear mixing in an ultrahigh-Q cavity. This new comb generator offers unique potential for chip integration and access to high repetition rates. However, time-domain studies reveal an intricate spectral coherence behavior in this type of platform. In particular, coherent, partially coherent or incoherent combs have been observed using the same microresonator under different pumping conditions. In this work, we provide a numerical analysis of the coherence dynamics that supports the above experimental findings and verify particular design rules to achieve spectrally coherent microresonator combs. A particular emphasis is placed in u…

Optical Frequency Combs Generated in Silica Microspheres in the Telecommunication C-, U-, and E-Bands

2021

Optical frequency combs (OFCs) generated in microresonators with whispering gallery modes are demanded for different applications including telecommunications. Extending operating spectral ranges is an important problem for wavelength-division multiplexing systems based on microresonators. We demonstrate experimentally three spectrally separated OFCs in the C-, U-, and E-bands in silica microspheres which, in principle, can be used for telecommunication applications. For qualitative explanation of the OFC generation in the sidebands, we calculated gain coefficients and gain bandwidths for degenerate four-wave mixing (FWM) processes. We also attained a regime when the pump frequency was in t…

Two Borderline Works: The Miniature Classical Friezes by John Henning

2020

The plaster replicas of two miniaturized reproductions of the Parthenon and Bassae friezes are preserved at the Plaster Cast Gallery of the Department Cultures and Societies of the University of Palermo. The original reproductions were made by the Scottish carver John Henning in the first decades of the 19th century. These artefacts, although they have seldom captured the attention of the archaeologists, are of particular interest and from manifold points of view.

Augšvācu rakstu valodas ienākšana Rīgas rātes kancelejā 16. gadsimtā

2015

Darba tēma ir „ Augšvācu rakstu valodas ienākšana Rīgas rātes kancelejā 16. gadsimtā”. Augšvācu rakstu valodas attīstība ir iespējams viens no svarīgākajiem notikumiem vācu valodas attīstības vēsturē, kas dažādu vēsturisku iemeslu dēļ norit ne tikai Vācijas impērijas kancelejās, bet arī Rīgas pilsētas kancelejā. Šajā darbā tika pētīta vācu valodas attīstība Rīgas rātes rakstu valodā. Tika veikta dažādu Rīgas rātes tekstu analizē ar mērķi iegūt informāciju par augšvācu valodas attīstību izvēlētajos tekstos. Izvēlētie teksti ir apkopoti grāmatā Die Quellen der Rigischen Stadtrechts bis zum Jahr, kas ir daudzpusīgs vēsturisko tekstu avots.

Il reliquiario a sarcofago di Santa Ninfa a Palermo

2022

In full affirmation of the themes of the Counter-Reformation, the city of Palermo pays homage to one of its Patronesses with the creation of a monumental silver urn. Through the analysis of documentary sources and the necessary formal and stylistic surveys, the history of the precious sacred goldsmith's work is reconstructed