title: Large-mode enhancement cavities.
abstract: In passive enhancement cavities the achievable power level is limited by mirror damage. Here, we address the design of robust optical resonators with large spot sizes on all mirrors, a measure that promises to mitigate this limitation by decreasing both the intensity and the thermal gradient on the mirror surfaces. We introduce a misalignment sensitivity metric to evaluate the robustness of resonator designs. We identify the standard bow-tie resonator operated close to the inner stability edge as the most robust large-mode cavity and implement this cavity with two spherical mirrors with 600 mm radius of curvature, two plane mirrors and a round trip length of 1.2 m, demonstrating a stable power enhancement of near-infrared laser light by a factor of 2000. Beam radii of 5.7 mm × 2.6 mm (sagittal × tangential 1/e(2) intensity radius) on all mirrors are obtained. We propose a simple all-reflective ellipticity compensation scheme. This will enable a significant increase of the attainable power and intensity levels in enhancement cavities.
authors.affiliation: Max-Planck-Institut für Quantenoptik, Hans-Kopfermann-Str 1, 85748 Garching, Germany.
authors.forename: Henning
authors.initials: H
authors.lastname: Carstens
authors.forename: Simon
authors.initials: S
authors.lastname: Holzberger
authors.forename: Jan
authors.initials: J
authors.lastname: Kaster
authors.forename: Johannes
authors.initials: J
authors.lastname: Weitenberg
authors.forename: Volodymyr
authors.initials: V
authors.lastname: Pervak
authors.forename: Alexander
authors.initials: A
authors.lastname: Apolonski
authors.forename: Ernst
authors.initials: E
authors.lastname: Fill
authors.forename: Ferenc
authors.initials: F
authors.lastname: Krausz
authors.forename: Ioachim
authors.initials: I
authors.lastname: Pupeza
mesh_terms: D003198:Computer Simulation; D017076:Computer-Aided Design; D004867:Equipment Design; D019544:Equipment Failure Analysis; D007909:Lenses; D008962:Models, Theoretical; D012031:Refractometry / Q000295:instrumentation*; D020349:Surface Plasmon Resonance / Q000295:instrumentation*