Observation of spectral interference for any path difference in an   interferometer
  We report the experimental observation of spectral interference in a Michelson interferometer, regardless of the relationship between the temporal path difference introduced between the arms of the interferometer and the spectral width of the input pulse. This observation is possible by introducing the polarization degree of freedom into a Michelson interferometer using a typical weak value amplification scenario. 
Luis Jose Salazar-Serrano, Alejandra Valencia and Juan P. Torres
physics.optics