A method of detecting and processing signals from particles, the method comprising: passing particles through a zone of a channel, wherein each particle includes a label, and only a subset of the particles include an analyte; producing a collimated light beam; blocking a transverse portion of the collimated light beam to generate a partially blocked light beam having a shadow region; focusing the partially blocked light beam on the zone of the channel, such that interaction of the focused, partially blocked light beam with the particles deflects light into a portion of the shadow region located optically downstream of the zone, and induces photoluminescence from the label; detecting a deflection signal from the portion of the shadow region as a function of time using a first detector, to generate deflection data, and a photoluminescence signal from the zone as a function of time using a second detector, to generate photoluminescence data; identifying particle waveforms in the deflection data, the particle waveforms corresponding to respective particles, at least a subset of the particle waveforms in the deflection data being double-peak waveforms each including a pair of peaks corresponding to a particle entering and exiting the zone; obtaining amplitudes from the photoluminescence data, the amplitudes corresponding to respective particles and their particle waveforms, at least a subset of the amplitudes corresponding to the double-peak waveforms; and assigning individual particles as including the analyte or not including the analyte based on the corresponding amplitudes; wherein the zone has a width measured parallel to a direction of particle travel through the zone, wherein the particles have a dimension measured parallel to the direction of particle travel as each particle passes through the zone, and wherein the width of the zone is less than the dimension of the particles. passing particles through a zone of a channel, wherein each particle includes a label, and only a subset of the particles include an analyte; producing a collimated light beam; blocking a transverse portion of the collimated light beam to generate a partially blocked light beam having a shadow region; focusing the partially blocked light beam on the zone of the channel, such that interaction of the focused, partially blocked light beam with the particles deflects light into a portion of the shadow region located optically downstream of the zone, and induces photoluminescence from the label; detecting a deflection signal from the portion of the shadow region as a function of time using a first detector, to generate deflection data, and a photoluminescence signal from the zone as a function of time using a second detector, to generate photoluminescence data; identifying particle waveforms in the deflection data, the particle waveforms corresponding to respective particles, at least a subset of the particle waveforms in the deflection data being double-peak waveforms each including a pair of peaks corresponding to a particle entering and exiting the zone; obtaining amplitudes from the photoluminescence data, the amplitudes corresponding to respective particles and their particle waveforms, at least a subset of the amplitudes corresponding to the double-peak waveforms; and assigning individual particles as including the analyte or not including the analyte based on the corresponding amplitudes; wherein the zone has a width measured parallel to a direction of particle travel through the zone, wherein the particles have a dimension measured parallel to the direction of particle travel as each particle passes through the zone, and wherein the width of the zone is less than the dimension of the particles.