Experimental Implementation of Multi-Resonant Laser Isotope Separation for Strontium Isotope Enrichment

We report on the laboratory development and initial implementation of a Multi-Resonant Laser Isotope Separation (MRLIS) [1] system for producing enriched strontium isotopes, targeting applications such as metabolic tracers (e.g., for bone health studies) and precision tests of quantum mechanics. Our approach integrates a planar Fabry-Pérot cavity to enable efficient, continuous-wave (CW) photoionization through resonant intracavity power buildup. This design overcomes the challenges of low photoionization cross-sections and limited CW laser powers by delivering high intracavity power density across an ultra-large mode volume, thus saturating ionization of the targeted isotope. We present initial experimental results demonstrating isotopic enrichment in Sr, including measured enrichment factors and ionization yield dependence on cavity alignment and laser power.