A linear stage moves a laser along the collection plate of an electrospinning device. The stage supports the laser that is moved through the electrospinning/electrospraying deposition field by a continuous rotation servo motor. Stage movement is controlled by a control unit. Signal voltages collected are sectioned into concentric layers so that the extinction coefficient for each layer can be calculated without including the extinction coefficient from the previous layer. The extinction coefficients were used in the Beer-Lambert law to determine the diameter of fibers being deposited on the collection plate as well as the concentration of fibers deposited indicating deposition speed.