Stroboscopic technique for measuring magnetic-field waveforms utilizing magneto-optical effect

Electromagnetic interference (EMI) is a serious problem in integrated circuits (ICs). Many methods for measuring EMI have been developed. These methods generally use metal probes to measure electromagnetic waves; however, metal probes alter the electromagnetic field. Furthermore, measurement techniques that have very high time resolutions are required because of the high operating frequencies of ICs. Measurements that use the magneto-optical effect can overcome both these problems. Magneto-optical materials affect electromagnetic waves less than metal probes and optical measurements are advantageous for minimally invasive measurements of magnetic fields. To achieve a high resolution, we developed a stroboscopic method that employs short laser pulses. This method can measure a magnetic field in any phase because the laser pulses are synchronized with the magnetic field. Measurements of magnetic-field waveforms demonstrated that this stroboscopic method is effective for measuring magnetic-field waveforms.