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

Abstract

We report the successful implementation of a surface-wave enabled dark-field aperture (SWEDA) directly on a complementary metal-oxide semiconductor sensor pixel (2.2μm), 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 = 3.96 W/m2, integration time = 5 ms), 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). © 2010 Optical Society of America.