Improving weak-signal identification via predetection background suppression by a pixel-level, surface-wave enabled dark-field aperture.

We report the successful implementation of a surface-wave enabled dark-field aperture (SWEDA) directly on a complementary metal-oxide semiconductor sensor pixel (2.2mum). This SWEDA pixel allows predetection cancellation of a uniform coherent background. We show that the signal-to-noise ratio (SNR) of the SWEDA pixel is better than that of a single undressed pixel over a significant range of signal-to-background ratio (SBR). For a small SBR value (SBR=0.001, background intensity=3.96W/m(2), integration time=5ms), we further demonstrate that a SWEDA pixel can detect a weak localized signal buried in a high background, while conventional postdetection background subtraction cannot (improved SNR=2.2 versus SNR=0.26).