Plasmonics has started to facilitate the replacement of bulky optical components in optical systems by compact nanometallic elements that perform the same function. This allows for a natural and very dense integration with electronic devices. In this vein, we present a silicon (Si) photodetector integrated with a set of plasmonic structures that can be used as either a broadband linear-Stokes polarimeter or a narrowband fullStokes polarimeter capable of determining the complete state of polari zation of a light beam. At a probe-wavelength of 830 nm, our experimental results show contrast ratios of 25 and 1.13 for orthogonal linear and circular states of polarization, in good agreement with simulations. The resulting device is lightweight, orders of magnitude smaller than conventional polarimeters, and mechanically robust. For these reasons, there promises to be a wide range of applications including polarimetric imaging and sensing.Keywords: Surface plasmon; polarization selective devices; polarimetry.Polarization is a property of light that describes the vector nature of its electric fi eld oscillations. Since polarization information is not correlated with the intensity or spectral information of light, use of polarized light has added superb capabilities to a wide range of applications including optical communications, imaging, microscopy, and sensing. In such applications, the state of polarization is typically monitored with the help of bulky optical components. It is by now wellestablished that nanometallic (i.e., plasmonic) structures can be engineered to produce an optical response that is strongly polarization-dependent [1 -9] . Very recently, the use of plasmonic crystals in free-space polarimetric systems has even been demonstrated [10,11] . Here, we show how to fully integrate plasmonic polarimetry functions with a Si-based photodetector. Such an integrated plasmonic polarimeter enables an accurate measurement of the complete state of polarization of light. Whereas conventional polarimetry approaches rely on the use of large optical components such as rotating polarizers and retardation wave plates, [12,13] this work shows that a compact platform can achieve the same functions. This work adds to a growing body of literature where plasmonic elements can be integrated with semiconductor elements to produce photodetectors with enhanced optical responses, integration advantages, or new, built-in optical functionalities [14 -17] .A set of four parameters is required to completely describe the state of polarization of an arbitrary polarized electromagnetic wave [12] . Experimentalists commonly use the Stokes parameters (S 0 , S 1 , S 2 , S 3 ) for this purpose as these parameters are conveniently measured as a sum or difference of measurable light intensities after light passes through polarization sensitive fi lters [18] . We have designed a compact plasmonic photodetector structure with which these parameters can be quantifi ed in a quick and convenient fashion through a set of photocurrent mea...