Fully dielectric pigtailed electro-optic sensors have been developed to quantify the energy absorbed by biological tissues exposed to radiofrequency telecommunication signals (GSM, UMTS, Wi¯, WIMAX). Both applied electric ¯eld and temperature are simultaneously measured, leading to the speci¯c absorption rate (SAR) which constitutes the reference parameter for microwave dosimetric applications. Measurements have been performed in the air and in a biological solution. In the frequency-domain, the electro-optic (EO) probe presents a dynamic range exceeding 70 dB and a sensitivity of 200mV/m¢Hz1=2 in the biological medium. As it presents an intrinsic °at response from quasi DC to 20 GHz, electro-optic probes have also been used in the time-domain to perform ¯rst in situ measurements of ultrashort electric pulses in an electroporation cuvette. A temperature probe sensitivity of 3mK has been reached.