Laser spectroscopy on a ‘‘shoestring’’ Available to Purchase

The advent of tunable lasers has had a profound influence on both experimental and theoretical physics. Unfortunately, since these laser systems are typically hazardous and expensive, the physics student at the undergraduate or first‐year graduate level has no real familiarity with their application in modern physics; and thus cannot fully appreciate their significance. Tunable single mode laser diodes, however, may offer a remedy to this situation. To demonstrate their applicability, we have designed a relatively simple and inexpensive experiment of laser diode spectroscopy in an atomic beam which illustrates the effect of hyperfine structure and the isotope shift in the rubidium D₁ transition (5²S_1/2−5²P_1/2). Furthermore, this experiment demonstrates the possibility of investigating basic physics without major expenditures for laser systems and laboratory facilities.