  We propose an interferometry experiment for the detection of axion-like
particles (ALPs). As in ordinary photon-regeneration (light shining through a
wall) experiments, a laser beam traverses a region permeated by a magnetic
field, where photons are converted to ALPs via the Primakoff process, resulting
in a slight power loss and phase shift. The beam is then combined with a
reference beam that originates from the same source. The detection of a change
in the output intensity would signal the presence of ALPs (or possibly other
particles that couple to the photon in a similar way). Because only one stage
of conversion is needed, the signal is of ${\cal O}(g^2_{a\gamma \gamma})$, as
opposed to ${\cal O}(g^4_{a\gamma \gamma})$ for photon-regeneration
experiments, where $g_{a\gamma \gamma}$ is the coupling between ALPs and
photons. This improvement over photon-regeneration is nullified by the presence
of shot noise, which however can be reduced by the use of squeezed light,
resulting in an improvement in the sensitivity to $g_{a\gamma\gamma}$ over
ordinary photon-regeneration experiments by an order of $10^{1/2}$ assuming
$10{\rm dB}$ noise suppression. Additionally, our setup can incorporate
straightforwardly optical delay lines or Fabry-Perot cavities, boosting the
signal by a factor of $n\sim10^3$, where $n$ is the number of times the laser
beam is folded. This way, we can constrain $g_{a\gamma\gamma}$ better by yet
another factor of $n^{1/2}\sim 10^{1.5}$, as compared to the $n^{1/4}$ boost
that would be achieved in photon-regeneration experiments.
