Four-wave mixing source of squeezed light for image processing and interferometry

A four-wave mixing squeezed light source comprising:

• a mixing medium having chi(3) non-linear characteristics including two atomic ground states coupled to each other by transitions through optically-excited states;
• a means for injecting into said mixing medium a pump beam having a pump beam polarization and a pump beam frequency, said pump beam frequency being near the ground-to-excited atomic transition but far enough from the ground-to-excited atomic transition such that the pump beam is substantially unabsorbed;
• and
• a means for injecting into said mixing medium a probe beam having a probe beam polarization that is orthogonal with respect to the pump beam polarization, the probe beam having a probe beam frequency of substantially at least one of:
• (i) said pump beam frequency minus a frequency splitting of the two atomic ground states;
• and (ii) said pump beam frequency plus said frequency splitting of the two atomic ground states;
• said mixing medium, said pump beam and said probe beam interacting to produce a phase conjugate beam having a phase conjugate beam frequency range and a phase conjugate beam polarization that is orthogonal to the pump beam polarization, such that said probe beam polarization and said phase conjugate beam polarization are non-degenerate with the pump beam, and the probe beam is amplified.