pulsing circulating target objects comprising red blood cells and at least one clot within the circulatory vessel with at least one pulse of laser energy at a first pulse wavelength ranging between 400 nm and 2500 nm, wherein the first pulse wavelength induces a photoacoustic signal from the circulating target objects, wherein the at least one clot is a hemoglobin-rich red clot, a platelet-rich white clot, or a combination thereof and wherein the hemoglobin-rich clot is light absorbing and the platelet-rich white clot is non-absorbing;

obtaining a photoacoustic pattern induced by the at least one pulse of laser energy, wherein the photoacoustic pattern comprises at least one photoacoustic signal comprising a blood background signal produced by the red blood cells;

simultaneously obtaining fluorescence, scattering, and photothermal signals from the target objects, via a photodetector;

processing photoacoustic, fluorescence, scattering, and photothermal signals;

analyzing a combination of the photoacoustic pattern and the fluorescence, scattering, and/or photothermal signals to determine the presence of the at least one clot, wherein analyzing the photoacoustic pattern comprises determining the presence of positive and negative contrast peaks in the photoacoustic pattern indicating the presence of a red clot, a white clot, or a combination thereof, wherein the negative contrast in the photoacoustic pattern below the blood background signal indicates the presence of the white clot, the positive contrast in the photoacoustic pattern above the blood background signal indicates the presence of the red clot, and a combination of positive contrast and negative contrast indicates the presence of a combination of red and white clots; and

producing a detection signal when the photoacoustic pattern and the fluorescence signal, scattering signal, photothermal signal, or combinations thereof indicates the presence of a clot.