Publications by authors named "A Garzarella"
In an effort to optimize magnetic field detection sensitivities, the Faraday responsivity vector, which determines the relationship between the Faraday rotation angle and an externally applied magnetic field, was investigated in magneto-optic sensors based on bismuth-doped iron-garnet films. Under externally applied fields, Faraday rotation is produced principally by domain rotation and domain wall motion, whose relative contributions depend on the domain geometry and the direction of laser propagation. When optically probed along a principal magnetization axis, Faraday rotation is driven by a single magnetization mechanism, and the responsivity is linearized (reduced to an effective Verdet constant).
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- Electro-optic (EO) crystals are chosen for electric field measurements based on their EO coefficients and dielectric constants, but traditional metrics often mispredict their sensitivity.
- Depolarization effects, usually overlooked, can significantly boost the responsiveness of EO materials, influenced by the shape and orientation of the crystals.
- For achieving maximum sensitivity, these depolarization effects are particularly effective in longitudinal EO sensors, leading to an optical modulation depth that increases with the square of the crystal length.
Article Synopsis
- Electro-optic (EO) modulation devices use electric fields to control optical beams, but they can be influenced by unwanted effects that alter light polarization.
- Even minor changes in the EO material's properties can cause significant variations in the optical signal's amplitude and phase, leading to instability.
- A new analysis method is introduced that mitigates these fluctuations, ensuring the EO device operates effectively, with potential applications in detecting and measuring electric fields.
The sensitivity of an electro-optic (EO) field sensor depends inversely on the dielectric constant of the nonlinear crystal. In EO sensors based on lithium niobate the effective value of this dielectric constant is affected by dielectric relaxation effects and is identified with its smaller, high-frequency component. Because of this effect, the EO modulation is significantly enhanced, thus improving the field strength sensitivity.
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