102,051 research outputs found
Phase-modulated cavity magnon polaritons as a precise magnetic field probe
No full textWe describe and operate a spin-magnetometer based on the phase modulation of cavity magnon polaritons. In this scheme a rf magnetic field is detected through the sidebands it induces on a pump, and the experimental configuration allows for a negligible pump noise and a high-frequency readout. The demonstrator setup, based on a copper cavity coupled to an yttrium iron garnet sphere hybrid system, reached a sensitivity of 2.0 pT/√Hz at 220 MHz, evading the pump noise and matching the theoretical predictions. An optimized setup can attain a rf magnetic field sensitivity of about 8 fT/√Hz at room temperature. An orders of magnitude improvement is expected at lower temperatures, making this instrument one of the few magnetometers accessing the subfemtotesla limit
Frequency locking to a high-finesse Fabry-Perot cavity of a frequency doubled Nd:YAG laser used as the optical modulator
No full textWe report on the frequency locking of a frequency doubled Nd:YAG laser to a 45 000 finesse, 87-cm-long, Fabry–Perot cavity using a modified form of the Pound–Drever–Hall technique. Necessary signals, such as light phase modulation and frequency correction feedback, are fed directly to the infrared pump laser. This is sufficient to achieve a stable locking of the 532 nm visible beam to the cavity, also showing that the doubling process does not degrade laser performances
Experimental searches for extra-gravitational forces in the submillimeter range
No full textWe report on our efforts to give direct limits to the existence of forces other than gravitational ones in the submillimetre range. The technique used involves looking at the expected shifts to the resonant frequency of microresonators whose motion is monitored through a fibre optic interferometer
Measurement of the Casimir force betweenparallel metallic surfaces
No full textWe report on the measurement of the Casimir force between conducting surfaces in a parallel configuration. The force is exerted between a silicon cantilever coated with chromium and a similar rigid surface and is detected by looking at the shifts induced in the cantilever frequency when the latter is approached. The scaling of the force with the distance between the surfaces was tested in the 0.5-3.0 mum range, and the related force coefficient was determined at the 15% precision level
Optical Manipulation of a Magnon-Photon Hybrid System
No full textWe demonstrate an all-optical method for manipulating the magnetization in a 1-mm yttrium-iron-garnet (YIG) sphere placed in a â 1⁄40.17 T uniform magnetic field. A harmonic of the frequency comb delivered by a multi-GHz infrared laser source is tuned to the Larmor frequency of the YIG sphere to drive magnetization oscillations, which in turn give rise to a radiation field used to thoroughly investigate the phenomenon. The radiation damping issue that occurs at high frequency and in the presence of highly magnetizated materials has been overcome by exploiting the magnon-photon strong coupling regime in microwave cavities. Our findings demonstrate an effective technique for ultrafast control of the magnetization vector in optomagnetic materials via polarization rotation and intensity modulation of an incident laser beam. We eventually get a second-order susceptibility value of â 1⁄410-7 cm2/MW for single crystal YIG
Testing the neutrality of matter by acoustic means in a spherical resonator
No full textMeasurements to test the neutrality of matter by acoustic means are reported. The apparatus is based on a spherical capacitor filled with gaseous SF_6 excited by an oscillating electric field. The apparatus has been calibrated measuring the electric polarizability. Assuming charge conservation in the β decay of the neutron, the experiment gives a limit of \epsilon_{p−e} <= 1 × 10−21 for the electron-proton charge difference, the same limit holding for the charge of the neutron. Previous measurements are critically reviewed and found to be inaccurate
Erratum to: A polarisation modulation scheme for measuring vacuum magnetic birefringence with static fields (The European Physical Journal C, (2016), 76, 5, (294), 10.1140/epjc/s10052-016-4139-0)
No full textIn the original article unfortunately we missed two typos in the equation for I(δ) at the top of the fourth page of the article. © 2017, The Author(s)
The Casimiro experiment: dynamical detection of Casimir forces
No full textT. Piran editor, World Scientific, Singapor
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