Atomic Clocks and Coherent Population Trapping: Experiments for Undergraduate Laboratories

摘要

We demonstrate how to construct and operate a simple and affordableexperimental apparatus, appropriate for an undergraduate setting, in order toproduce and study coherent effects in atomic vapor and to investigate theirapplications for metrology. The apparatus consists of a vertical cavity surfaceemitting diode laser (VCSEL) directly current-modulated using a tunablemicrowave oscillator to produce multiple optical fields needed for theobservation of the coherent population trapping (CPT). This effect allows veryaccurate measurement of the transition frequency between two ground statehyperfine sublevels (a "clock transition"), that can be used to construct aCPT-based atomic clock.