Nolan, SamuelHaine, SimonSzigeti, Stuart2026-01-012026-01-019781943580262ORCID:/0000-0002-3015-6511/work/163626731https://hdl.handle.net/1885/733801191We show that optimal and robust quantum metrology can be achieved without echoes. Specifically, we explore optimal measurement strategies with and without detection noise, and in both situations, find that echoes are unnecessary.enPublisher Copyright: © OSA 2017.201710.1364/QIM.2017.QT6A.5585036457453