1,721,105 research outputs found
A geometric (Pancharatnam) phase approach to the polarization and phase control in the coherent optics circuits
No full textThe control of the state of polarization and of the phase shift represents an important task in developing coherent optics circuits. The paper introduces a novel control strategy based on the concept of geometric, or Pancharatnam, phase. This phase is topological in nature and it appears when a closed loop is traced on the Poincaré sphere. The aspects concerning the polarization control are analyzed for three generic input states: circular, linear and elliptical. For each situation, the evolution of the geometric and dynamic phase is given together with the control circuit design. Similar concepts are applied also to phase control in the coherent detection. The analysis points out that only a design based on the concept of “geometric phase” permits the developing of control systems intrinsically endless
Spintronic Biosensors with active area localized on a magnetic domain wall
No full textBiosensori spintronici con area attiva localizzata su una parete di dominio magnetic
Novel method to pseudoheterodyne a polarimetric fiber optic sensor
No full textThe insertion of a rotating halfwave plate (RHWP) into a polarimetric fiber optic scheme is analyzed. The RHWP allows phase control of the autointerference signal and can be used to pseudoheterodyne the polarimetric setup. The scheme is applied to a polarimetric sensor of a dynamic strain and permits full recovery of the elongation signal
Quasi-distributed single-length polarimetric sensor
No full textA quasi-distributed polarimetric sensor employing a single length of polarization-preserving fiber is described. The sensing segments are identified by miniature rings that squeeze the fiber to couple power from one optical mode to the orthogonal mode while avoiding any mechanical damage to the fiber. A superluminescent-diode source allows us to exploit the coherent-multiplexing concept, which yields high resolution and high precision. Experimental results confirm this approach and point toward the development of a quasi-distributed sensor with polarimetric sensitivity, high spatial resolution, and fiber-optic mechanical integrity
A coherence-multiplexed quasi-distributed polarimetric sensor suitable for structural monitoring
No full text
Guided-wave rotating retarder
No full textA guided-wave rotating retarder has been developed. The device is based on the generation of a rotating elasto-optics effect by the contemporary application of three 120-degrees space-phased and time-phased forces. A first experiment made by using a GRIN lens is reported. A retarder with 1 radian of magnitude is obtained which can rotate 180 degrees. The magnitude and the rotation of the device axis are continuously adjustable. The device can be exploited also for fiber-optic components and it constitutes the basis for endless polarization compensators
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