2021/02/04 by M. Sumetsky, Sumetsky, M.
Engineering · Physics and Astronomy · #Advanced Fiber Laser Technologies #FOS: Physical sciences #Mechanical and Optical Resonators #Optics (physics.optics) #Photonic and Optical Devices #physics.optics
paper · pdf · doi:10.48550/arxiv.2102.02749
4 pages, 2 figures
arxiv created 2021/02/04 · openalex publication_date 2021/02/04 · arxiv updated 2021/02/05 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We determine the fundamental limit of the microresonator field uniformity. It can be achieved in a specially designed microresonator, called a bat microresonator, fabricated at the optical fiber surface. We show that the relative nonuniformity of an eigenmode amplitude along the axial length L of an ideal bat microresonator cannot be smaller than (1)/(3)π2n4rλ-4Q-2L4, where nr, λ and Q are its refractive index, the eigenmode wavelength and Q-factor. In the absence of losses (Q=∞ ), this eigenmode has the amplitude independent of axial coordinate and zero axial speed (i.e., is stopped) within the length L. For a silica microresonator with Q=108 this eigenmode has the axial speed ∼ 10-4c, where c is the speed of light in vacuum, and its nonuniformity along the length 100 micron at wavelength λ=1.5 micron is ∼ 10-7. For a realistic fiber with diameter 100 micron and surface roughness 0.2 nm, the smallest eigenmode nonuniformity is ∼ 0.0003. As an application, we consider a bat microresonator evanescently coupled to high Q-factor silica microspheres which serves as a reference supporting the angstrom-precise straight-line translation over the distance L exceeding a hundred microns.