title: Alternating current sensor with second-harmonic detection.
abstract: We describe a novel optical sensor based on the Faraday effect for measuring ac. The sensing element is a piece of material of high Verdet constant placed between polarizers. When the angle between the polarizers differs by 45 degrees, a signal of twice the frequency of the ac is generated--in addition to the usual signal with the same frequency as the current. The quotient of these two signals allows a normalized output to be obtained that is proportional to the amplitude of the current. Experimental results demonstrating the practicality of the procedure are presented.
authors: Instituto de Física, Facultad de Ingeniería, J. Herrera y Reissig 565, 11300 Montevideo, Uruguay. jferrari@fing.edu.uy
authors: J A
authors: JA
authors: Ferrari
authors: C D
authors: CD
authors: Perciante
authors: A
authors: A
authors: Dubra
authors: A
authors: A
authors: Arnaud
authors: E M
authors: EM
authors: Frins