Low Noise Near-Concentric Optical Cavity Design

Near-concentric cavities are excellent tools for enhancing atom--light interaction as they combine a small mode volume with a large optical access for atom manipulation. However, they are sensitive to longitudinal and transverse misalignment. To address this sensitivity, we present a compact near-concentric optical cavity system with a residual cavity length variation $\delta L_{C, rms}$=36(9) pm. A key part of this system is a cage-like tensegrity mirror support structure that allows to correct for longitudinal and transverse misalignment. The system is stable enough to allow the use of mirrors with higher cavity finesse to enhance the atom--light coupling strength in cavity-QED applications.