Pump–probe spectroscopy with copropagating pump and probe beams of an open two-level system where, as a result of inelastic collisions, the lower state of an optical transition relaxes faster to reservoir states than the upper state does, may yield an antihole in the probe spectral profile whose linewidth is subnatural and unaffected by Doppler broadening.
© 1989 Optical Society of America
Original Manuscript: October 12, 1988
Manuscript Accepted: January 31, 1989
Published: April 15, 1989
A. D. Wilson-Gordon and H. Friedmann, "Ultranarrow extraresonant antiholes in pump–probe spectroscopy induced by inelastic collisions," Opt. Lett. 14, 390-392 (1989)