Understanding and suppressing backscatter in optical resonators

• DOI: 10.48550/arxiv.2205.05203
• Publication Date: 2022-01-01
• Authors: Matt Jaffe; Lukas Palm; Claire Baum; Lavanya Taneja; Aishwarya Kumar; Jonathan Simon
• Keywords: Backscatter (email)

Optical cavities have found widespread use in interfacing to quantum emitters. Concerns about backreflection and resulting loss, however, largely prevented the placement of optics such as lenses or modulators within high-finesse cavities. In this work, we demonstrate a million-fold suppression backreflections from twisted optical cavity. We achieve by quantitatively exploring backscatter Fabry-Pérot resonators, separating effect into three physical sectors: polarization, mode envelope spatial profile. describe impact each these sectors, how minimize each. This culminates measured effective reflectivities below part-per-billion level for fundamental mode. Additionally, show that beams carrying orbital angular momentum experience up $10^{4}$ times additional suppression, limited only density states other cavity modes. Applying ideas laser gyroscopes could strongly suppress lock-in, thereby improving sensitivity at low rotation rates.