Changes

The [[NeoScan]] real-time field measurement & scanning system provides an entirely new capability for the measurement of high-intensity electric fields. This technology is based on the Pockel’s effect which measures the phase-retardance of an optical beam due to an impinging electric field. This electro-optic effect is observed in non-centrosymmetric crystals when an electric field is directed along certain crystal axes causes a change in the indices of refraction encountered by an incident optical beam. Figure 1.1 shows the basic principle of the electro-optic effect. The electro-optic effect provides a means of modulating the phase or intensity of the optical radiation. In another sense, this effect also makes it possible to detect the presence of an electric field impinging on the crystal. The polarization of an optical beam travelling through a crystal is altered by the electric field in that crystal. The comparison of polarization states allows determination of the amplitude and phase of the existing RF electric field. Since the electro-optic sensing phenomenon relies on small displacements of the atomic crystal structure, the response time of the process is extremely short. This short response time makes it possible to measure high-frequency electric fields up to the terahertz regime.

A typical EO probe is composed of an optical fiber affixed with an EO crystal coated with a dielectric reflection layer on its bottom surface as shown in Figure 1.2. These probes have very delicate optical interconnects and extreme care must be taken in handling the probes to prevent excessive shock, bending and out of plane stresses.