Impurity Fe3+ ion electron spin resonance (ESR) spectroscopy using multiple dielectric modes in a SrTiO3 dielectric resonator has been performed with a tunable DC magnetic field of up to 1.6 T. The ...Ti ion is substituted by Fe3+ ion forming FeO6 octahedral complex with an iron-oxygen-vacancy (Fe). In such a metal-ligand complex, a giant g-factor of was observed in the ferroelectric phase at 20 mK. The change of Fe3+ ion center-symmetry in the FeO6 complex as a soft-mode characteristics of ferroelectric phase transition and the influences of iron-oxygen-vacancy (Fe), are interactively sensitive to asymmetry in the octahedral rotational parameter Φ in SrTiO3.
We present cavity QED experiments with an Er super(3+): Y sub(2) SiO sub(5) crystal magnetically coupled to a three-dimensional (3D) cylindrical sapphire loaded copper resonator. Such waveguide ...cavities are promising for the realization of a superconducting quantum processor. Here, we demonstrate the coherent integration of a rare-earth spin ensemble with the 3D architecture. The collective coupling strength of the Er super(3+) spins to the 3D cavity is 21 MHz. The cylindrical sapphire loaded resonator allowed us to explore the anisotropic collective coupling between the rare-earth doped crystal and the cavity. This work shows the potential of spin doped solids in 3D quantum circuits for application as microwave quantum memories as well as for prospective microwave to optical interfaces.
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•Whispering Gallery multi-mode ESR with high precision in SrLaAlO4 at 20mK temperature.•Identification of Cu2+, Fe3+ and Mn4+ impurity paramagnetic ions in SrLaAlO4•Spin parameters ...and anisotropy of Cu2+ ion along with site symmetry in the crystal at 20mK.•Spin parameters and anisotropy of Fe3+ ion along with site symmetry in the crystal at 20mK.•Spin parameters and anisotropy of Mn4+ ion along with site symmetry in the crystal at 20mK.
A cylindrical single crystal SrLaAlO4 Whispering Gallery mode dielectric resonator was cooled to millikelvin temperature using a dilution refrigerator. By controlling a DC-magnetic field, impurity ions’ spins were coupled to a variety of modes allowing the measurement of hybrid spin-photon systems. This Electron Spin Resonance mapping technique allowed us to detect Cu2+,Fe3+ and Mn4+ impurity ions (at the level of parts per million (ppm) to parts per billion (ppb)), verified by the measurement of the spin parameters along with their site symmetry. Whispering Gallery modes exhibited Q-factors ⩾105 at a temperature less than 20mK, allowing sensitive spectroscopy with high precision. Measured hyperfine line constants of the Cu2+ ion shows different parallel g-factors, g‖Cu, of 2.526,2.375,2.246 and 2.142. The spin-orbit coupling constant of the Cu2+ ion was determined to be λ≃-635cm-1. The low-spin state Fe3+ ion’s measured parallel g-factor, g‖Fe, of 2.028 reveals tetragonal anisotropy. The Mn4+ ion is identified in the lattice, producing hyperfine structure with high-valued g-factors,g‖Mn, of 7.789,7.745,7.688,7.613,7.5304 and 7.446. The hyperfine structures of the Cu2+ and Mn4+ ions show broadening of about 79G between 9.072GHz and 10.631GHz, and 24.5G broadening between 9.072GHz and 14.871GHz, respectively.
The impurity paramagnetic ion, Cu2+ substitutes Al in the SrLaAlO4 single crystal lattice, this results in a CuO6 elongated octahedron, and the resulting measured g-factors satisfy four-fold axes ...variation condition. The aggregate frequency width of the electron spin resonance with the required minimum level of impurity concentration has been evaluated in this single crystal SrLaAlO4 at 20 millikelvin. Measured parallel hyperfine constants, A∥Cu, were determined to be −155.7×10−4 cm−1, −163.0×10−4 cm−1, −178.3×10−4 cm−1 and −211.1×10−4 cm−1 at 9.072 GHz (WGH4,1,1) for the nuclear magnetic quantum number MI=+32,+12,−12, and −32 respectively. The anisotropy of the hyperfine structure reveals the characteristics of the static Jahn-Teller effect. The second-order-anisotropy term, ∼(spin−orbit coupling10Dq)2, is significant and cannot be disregarded, with the local strain dominating over the observed Zeeman-anisotropy-energy difference. The Bohr electron magneton, β=9.23×10−24JT−1, (within −0.43% so-called experimental error) has been found using the measured spin-Hamiltonian parameters. Measured nuclear dipolar hyperfine structure parameter P∥=12.3×10−4 cm−1 shows that the mean inverse third power of the electron distance from the nucleus is 〈rq−3〉≃5.23 a.u. for Cu2+ ion in the substituted Al3+ ion site assuming nuclear electric quadruple moment Q=−0.211 barn.
Whispering-gallery modes are used for very accurate permittivity, dielectric loss, and temperature coefficient of permittivity measurements for both isotropic and uniaxially anisotropic dielectric ...materials. The relationship between resonant frequencies, dimensions of the resonant structure, and permittivity of the sample under test is calculated with a radial mode-matching technique. The relative accuracy of these computations is better then 10/sup -4/. The influence of conductor losses on dielectric loss tangent determination is treated for both whispering-gallery-mode and TE/sub 01/spl delta//-mode dielectric-resonator techniques. Two permittivity tensor components of sapphire and their temperature dependence were measured from 4.2 to 300 K. The total uncertainty in permittivity when use is made of whispering-gallery modes was estimated to be less than 0.05%. The uncertainty was limited principally by uncertainty in sample dimensions. Experimental and calculated resonant frequencies of several whispering-gallery modes differed by no more than 0.01%. The dielectric loss tangent of sapphire parallel and perpendicular to its anisotropy axis was calculated to be less than 10/sup -9/ at 4.2 K. The permittivity and dielectric loss tangent of a commercially available low-loss high-permittivity ceramic material has also been measured at S- and C-band frequencies using a large number of whispering-gallery modes.
In this paper we describe the improved redesign of the microwave frequency synthesizers for Laboratoire National d'Essais-Systemes de Reference Temps-Espace (LNE-SYRTE) atomic fountains. The ...synthesizers use a cryogenic oscillator to generate both Cs and Rb hyperfine frequencies based on a new distribution frequency of 1 GHz. The main metrological features (phase noise, long-term phase stability, and spectral purity) of the synthesizers have been measured in situ connected to an atomic fountain and are compatible with an accuracy goal of 10 -16 for the atomic fountains. The simultaneous test of two different synthesizers on the FO2 atomic fountain at the 10 -16 level also is reported
The performance of an active frequency doubler used to generate a pump signal for a solid-state microwave amplification by stimulated emission of radiation (MASER) based on paramagnetic impurity ions ...in sapphire is reported. The frequency doubler has been characterised in terms of phase noise, power dependence and frequency stability (Allan variance) for an output frequency range between 20 and 40 GHz. With the measurement system referenced to a 10 MHz hydrogen MASER, the doubler exhibits a single sideband phase noise of ∼−108 dBc/Hz at 1 Hz offset frequency, from which an upper limit fractional frequency instability of about 2 × 10−16 at 1 s integration time is estimated.
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