ABSTRACT
Optical spectroscopy has proved to be an invaluable tool for probing atomic and molecular systems. The historical role of atomic spectroscopy in revealing quantum effects and validating quantum theory is well-documented, from the first interpretation of the Balmer series in hydrogen to the measurement of the Lamb shift in hydrogen, spectroscopy was the proving ground for the emergence of a comprehensive understanding of quantum effects. Small effects can reveal deep truths, so techniques that advance our ability to resolve closely spaced features are highly prized. Experimental methodologies and novel instrumentation are continually being developed, and today atomic and molecular physics play central roles in research efforts that address a wide range of fundamental and applied questions. The laser beam is well-collimated, with a power that likely exceeds 10 mW. The circular dichroism measurements that students make here, and also those in the saturated absorption lab that follows, are examples of absorption spectroscopy.
