  We create an optical frequency, polarization independent, narrow band-pass
filter of 1.3 GHz (3 dB bandwidth), using the steep dispersion near the
Rubidium D1 atomic transitions within a prism-shaped vapor cell. This enables
us to clean the amplified spontaneous emission from a laser by more than 3
orders of magnitude. Such a filter could find uses in fields such as quantum
information processing and Raman spectroscopy.

Optics