Towards a Practical Nonlinear Interferometer to Improve Sensor Signal to Noise Ratios (SNRs)

July, 2016
Nonlinear Interferometer Setup

The probe (dashed line) and pump (solid line) beams travel from left to right stimulating a conjugate beam (dotted line) in the nonlinear beam splitter.  Next, the probe samples a phase changing element (WP).  The three beams reflect from the mirror and pass back through the system.  In the second pass through the nonlinear beam splitter the probe and conjugate are amplified (or de-amplified) depending on the induced phase shift from WP.

Interferometry is used in many applications, from aviation to tests of fundamental physics.  Interferometers are used to convert a phase change into an intensity change for detection by mixing light on beam splitters.  Nonlinear interferometers, which use parametric amplifiers in place of beam splitters, can improve the signal to noise ratio of interferometric sensors by a factor of twice the power gain [1].  Recently ORNL has realized a novel, inherently stable, nonlinear interferometer using nonlinear rubidium vapor [2, 3].  This approach reduces the complexity and the size, weight and power requirements (SWAP) of earlier demonstrations.  However, it is still constructed using bulk, free-space optics on a lab table.  This project seeks to reduce SWAP further and perform measurements to quantify its performance relative to other approaches.

[1] Z. Y. Ou, Phys. Rev. A 85, 023815 (2012). 

[2] J. M. Lukens, N. A. Peters and R. C. Pooser,  "Improved Nonlinear Interferometer," Provisional US Patent Application #62/329,230 (2016).

[3] J. M. Lukens, N. A. Peters,  and R. C. Pooser, "A naturally stable Sagnac-Michelson nonlinear interferometer,” Optics Letters Vol. 41, Issue 23, p. 5438 (2016).


Principal Investigator

Nicholas A Peters


Department of Defense (DOD)