Rubidium Isotope Shift Measurement using Noisy Lasers

TL;DR

This paper demonstrates how undergraduate SAS experiments with rubidium and noisy lasers can effectively measure isotope shifts, improving understanding of atomic ground states and extending to advanced modulation transfer spectroscopy techniques.

Contribution

It provides a theoretical and experimental framework for using free-running laser diodes in isotope shift measurements and introduces an extended spectroscopy method.

Findings

Noisy lasers can be effectively used for isotope shift measurements.

Theoretical explanation supports experimental results.

Extension to modulation transfer spectroscopy enhances measurement capabilities.

Abstract

Data students collect from the typical advanced undergraduate laboratory on Saturated Absorption Spectroscopy (SAS) of rubidium can be used to measure the isotope shift and thus leads to an estimate of the isotopic ground state energy shift. This helps students refine their `picture' of the atomic ground state. We describe theoretically why this laboratory works well with free-running laser diodes, demonstrate it experimentally using these lasers tuned to either principal near-infrared transitions, and show an extension of the laboratory using the modulation transfer spectroscopy method.