Low-Coherence Reflectometry Through Scattering Media with Degenerate Four-Wave Mixing in a Thin Nonlinear Optical Layer

We have demonstrated the coherence filtering operation for optical low-coherence reflectometry via degenerate four-wave mixing (DFWM) in a thin nonlinear optical layer. To perform proof-of-principle DFWM experiments, we use a thin dye solution with a thermally-induced optical nonlinearity. In contrast to previous works, which used c.w. light-emitting diodes or Fourier-transform limited ultra-short laser pulses, we have used broad-band nanosecond laser pulses for depth resolved measurements through scattering media.