Thermo-optic designs for microwave and millimeter-wave electric-field probes

Various thermooptic designs are considered for electric-field probes for the approximate frequency range of 1-110 GHz. The designs are all based on using an optically sensed thermometer to measure the temperature rise of a resistive material in an electric field. Calculations of the sensitivities of the different designs, measurement results for the most easily fabricated design, and a discussion of possible improvements are presented. The results indicate that a probe based on this design could detect a minimum electric field of about 30-50 V/m