Characterization of electromagnetic fields using a lock-in infrared thermographic system

Electromagnetic fields can be monitored by infrared thermography, using sensitive paints or coatings deposited on structures or thin films. Enhancement of the method by release of convective losses and conduction effects is demonstrated. This is obtained by modulating the amplitude of the fields and using a lock-in thermographic system. Examples of application are given which concern an interference field and a multimode field inside a wave-guide.