A rotary stone cutting tool and method for making countertops and the like includes a shank shaped for detachable connection with a rotary drive. The device includes a pair of light-transmission substrates at least one of which is held freely movable in a way that a major surface thereof moves in a direction vertical to the optical path, and which have complementary curved surfaces facing, and apart from, each other. A first pump source is configured provides sufficient pump power in a plurality of first pump wavelengths to stimulate Raman scatteringgain in the optical fiber within the signal wavelength range. In one version of the method, the phenylbenzothiazole derivative is a compound of formula :. The EEG signal data complexity measure is used as the feedback signal in a control loop for an anesthetic delivery unit to control hypnotic drug administration to the patient in a manner that provides the desired hypnotic level in the patient.