Retro-reflections on mutually pumped phase conjugation: an incoherent reappraisal of this surprising behaviourRobert W. EasonPublished Jan 1, 2007• 0 citationsPublisherAbstractAfter two decades, the discovery of mutually pumped phase conjugation continues to surprise and impress (me). How come such an unexpected and optically illegal phenomenon didn’t make it big time and find applications in abundance?DOI10.1364/pr.2007.mc1