Modified Pockels sensor for electric-field measurements

Both sensitivity and resolution of a Pockels field measuring system have been much improved by using a light-intensity-difference method with a modulated laser beam. Experimental results show an increase in sensitivity of over 200 times from that of the original field measuring system, and resolution, a ratio of signal to noise (S/N), is improved by more than 30 dB at an applied field strength of 200 V/cm. The minimum measurable field strength is 5.0 V/cm of AC field strength at the S/N ratio of 10.2 dB and 1.0 V/cm at the critical value of 0 dB, where the signal voltage equals the noise. Furthermore, it is found that by introducing a reflection-mirror technique, the field measuring system can be further simplified