An apparatus for detecting a presence of a predetermined material within a sample uses signal generation circuitry for generating a first signal having a first distinct signature including a first eccentricity of a mode intensity, a first shift in a center of the mode intensity and a first rotation of an ellipsoidal intensity output of the mode intensity and applying the first signal to the sample. A detector receives the first signal after the first signal passes through the sample and detects a second distinct signature including a second eccentricity of the mode intensity, a second shift in the center of the mode intensity and a second rotation of the ellipsoidal intensity output of the mode intensity. The detector also determines the presence of the predetermined material within the sample based on the detected second distinct signature within the first signal received from the sample and provides an output of an indication of the presence of the predetermined material responsive to the determination.
