No abstract

We choose an alternative way using thermo-sensitive films which had been developed for infrared thermography method called EMIR (ElectroMagnetic InfraRed). Our objective in the present work is to replace IR thermography by thermo-fluorescence spectroscopy; thus we move to visible range, to improve the spatial resolution o f the images.

A novel and original method of LF magnetic field imaging is presented, that uses a magnetic thin film coated with fluorescent dye. Due to high permeability and consequent hysteresis losses, the film is heated by the field. As the fluorescence of the coated material is temperature-dependent, magnetic field mapping can be obtained in a short time and on a large surface by recording images with a S-CMOS camera. This principle had been previously presented in the microwave regime, for both electric and magnetic fields imaging; here we propose first results in the low frequency regime (kHz frequency range). Index Terms-Magnetic field imaging, thermography, thermo-fluorescence, magnetic coil I.

The characterization of the electromagnetic field emitted by various sources (antenna, radar...) is an important issue, either for civil or defense applications. The measurement of the electromagnetic field may be performed by a local probe, but the infrared thermography imaging is an alternative way. The latter method, called EMIR [1] (ElectroMagnetic InfraRed) has been used for years in particular at ONERA where it had been developed. We have recently successfully implemented this technique in the domain of visible light, named as EMVI [2]. As in the EMIR method, a thin film (sensitive to either electric field or magnetic field) is heated by the emitted field. But here the film is coated with a polymer doped with fluorescent molecules. As the fluorescent emission depends on the temperature of the film, we get a thermofluorescent sensor. The results presented here illustrate that new method: both magnetic and electric field imaging of a High Impedance Surface (HIS) has thus been obtained.