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

Abstract

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 presented description of resonators will help to analyze the effects of optical resonators, interpret the results of experiments, and guide the development of novel applications of microresonators.

Symmetry-Broken High-Q Terahertz Quasi-Bound States in the Continuum

“…Coupling techniques necessitate precise alignment and are additionally sensitive to fiber losses. , Furthermore, BIC-based metasurfaces can be easily fabricated using relatively simple nanofabrication methods, while certain WGMR geometries are less straightforward. For example, toroidal resonators typically demand a combination of nanofabrication techniques and CO 2 laser reflow, thereby complicating the fabrication process. − …”

Whispering Gallery Mode Resonator Temperature Compensation and Refractive Index Sensing in Glucose Droplets

“…In a simplified case, the WGMR resonance shift d f depends only on the termo-optical coefficient β and the expansion coefficient α. This dependence is linear from temperature T [25]:…”

Compact fiber microsphere coupling system and its temperature response characteristics

“…With the development of micro/ nano-machining technology, various of micro-cavities with extremely smooth surfaces have been designed, including micro-disk [2], micro-ring [3], micro-sphere [4] and micro-core ring [5]. High Q factor (up to 109) and small mode volume can be easily obtained in these kinds of micro-cavities [6][7][8], which has the more promising potential than Fabry-Perot micro-cavity [9] or photonic crystal micro-cavity [10]. The resonant frequency of WGMs is dependent on the morphological shape and material of micro-cavity, as well as the environmental parameters [11].…”