Shaped pulses for transient compensation in quantum-limited electron spin resonance spectroscopy (original) (raw)
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Review of Scientific Instruments, 2013
We discuss the design and implementation of thin film superconducting coplanar waveguide microresonators for pulsed ESR experiments. The performance of the resonators with P doped Si epilayer samples is compared to waveguide resonators under equivalent conditions. The high achievable filling factor even for small sized samples and the relatively high Q-factor result in a sensitivity that is superior to that of conventional waveguide resonators, in particular to spins close to the sample surface. The peak microwave power is on the order of a few microwatts, which is compatible with measurements at ultra low temperatures. We also discuss the effect of the nonuniform microwave magnetic field on the Hahn echo power dependence.
Inductive-detection electron-spin resonance spectroscopy with 65 spins/ Hz sensitivity
Applied Physics Letters, 2017
We report electron spin resonance spectroscopy measurements performed at millikelvin temperatures in a custom-built spectrometer comprising a superconducting micro-resonator at 7 GHz and a Josephson parametric amplifier. Owing to the small ∼10 −12 λ 3 magnetic resonator mode volume and to the low noise of the parametric amplifier, the spectrometer sensitivity reaches 260 ± 40 spins/echo and 65 ± 10 spins/ √ Hz, respectively.
Reaching the quantum limit of sensitivity in electron spin resonance
Nature nanotechnology, 2015
The detection and characterization of paramagnetic species by electron spin resonance (ESR) spectroscopy is widely used throughout chemistry, biology and materials science, from in vivo imaging to distance measurements in spin-labelled proteins. ESR relies on the inductive detection of microwave signals emitted by the spins into a coupled microwave resonator during their Larmor precession. However, such signals can be very small, prohibiting the application of ESR at the nanoscale (for example, at the single-cell level or on individual nanoparticles). Here, using a Josephson parametric microwave amplifier combined with high-quality-factor superconducting microresonators cooled at millikelvin temperatures, we improve the state-of-the-art sensitivity of inductive ESR detection by nearly four orders of magnitude. We demonstrate the detection of 1,700 bismuth donor spins in silicon within a single Hahn echo with unit signal-to-noise ratio, reduced to 150 spins by averaging a single Carr...
Electron spin resonance detected by a superconducting qubit
Physical Review B, 2012
A new method for detecting the magnetic resonance of electronic spins at low temperature is demonstrated. It consists in measuring the signal emitted by the spins with a superconducting qubit that acts as a single-microwave-photon detector, resulting in an enhanced sensitivity. We implement this new type of electron-spin resonance spectroscopy using a hybrid quantum circuit in which a transmon qubit is coupled to a spin ensemble consisting of NV centers in diamond. With this setup we measure the NV center absorption spectrum at 30 mK at an excitation level of ∼ 15 µB out of an ensemble of 10 11 spins.
Journal of Magnetic Resonance, 1998
The concept of microwave pulse matching is applied to threement is HYSCORE (hyperfine sublevel correlation), intropulse electron spin echo envelope modulation and sublevel correladuced by Höfer et al. (4) and developed further by Höfer tion (HYSCORE) spectroscopy. Matched pulses enhance the effiand others (5-10). HYSCORE makes use of the sequence ciency of forbidden transfers and may drastically increase the p/2-t-p/2-t 1 -p-t 2 -p/2-t-echo, with a fixed time t signal intensity of basic frequency and combination frequency and variable times t 1 and t 2 , incremented independently from transitions in these conventional pulse EPR experiments. The theeach other. The mw p pulse applied at time t 1 after the ory of matched pulses is extended to the case of strong and largely second p/2 pulse transfers the nuclear coherences in one isotropic hyperfine interactions, and numerical simulations are electron spin manifold to nuclear coherences in the other presented to gain a deeper insight into the inner working of the electron spin manifold. Standard HYSCORE again makes matched-pulse approach. It is shown that the enhancement of use of nonselective mw pulses, and the sensitivity of the combination frequencies in matched HYSCORE can be used to determine the relative sign of hyperfine coupling constants as well approach is again determined solely by the spin system.
2 1 A pr 2 01 2 Nonlinear Induction Detection of Electron Spin Resonance
2018
We present a new approach to the induction detection of electron spin resonance (ESR) signals exploiting the nonlinear properties of a superconducting resonator. Our experiments employ a yttrium barium copper oxide (YBCO) superconducting stripline microwave (MW) resonator integrated with a microbridge. A strong nonlinear response of the resonator is thermally activated in the microbridge when exceeding a threshold in the injected MW power. The responsivity factor characterizing the ESR-induced change in the system’s output signal is about 100 times larger when operating the resonator near the instability threshold, compared to the value obtained in the linear regime of operation. Preliminary experimental results, together with a theoretical model of this phenomenon are presented. Under appropriate conditions nonlinear induction detection of ESR can potentially improve upon the current capabilities of conventional linear induction detection ESR.
Journal of Magnetic Resonance, 2008
The construction and performance of a Q-band (35 GHz) cryogenic probehead for pulse electron paramagnetic resonance and continuous wave electron paramagnetic resonance measurements with down-scaled loop gap resonators (LGRs) is presented. The advantage of the LGR in comparison to TE 012 resonators lies in the large B 1 microwave (mw) fields that can be generated with moderate input mw power. We demonstrated with several examples that this allows optimal performance for double-quantum electron coherence, HYSCORE, and hyperfine decoupling experiments employing matched and high turning angle mw pulses with high B 1 -fields. It is also demonstrated that with very low excitation power (i.e. 10-40 mW), B 1 -fields in LGRs are still sufficient to allow short mw pulses and thus experiments such as HYSCORE with high-spin systems to be performed with good sensitivity. A sensitivity factor K rs of LGRs with different diameters and lengths is introduced in order to compare the sensitivity of different resonant structures. The electromagnetic field distribution, the B 1 -field homogeneity, the E 1 -field strength, and the microwave coupling between wave guide and LGRs are investigated by electromagnetic field calculations. The advantage and application range using LGRs for small sample diameters is discussed.
Journal of Magnetic Resonance, 2005
The design and performance of an electron spin resonance spectrometer operating at 3 and 9 GHz microwave frequencies combined with a 9-T superconducting magnet are described. The probehead contains a compact two-loop, one gap resonator, and is inside the variable temperature insert of the magnet enabling measurements in the 0-9 T magnetic field and 1.5-400 K temperature range. The spectrometer allows studies on systems where resonance occurs at fields far above the g 2 paramagnetic condition such as in antiferromagnets. The low quality factor of the resonator allows time resolved experiments such as, e.g., longitudinally detected ESR. We demonstrate the performance of the spectrometer on the NaNiO 2 antiferromagnet, the MgB 2 superconductor, and the RbC 60 conducting alkaline fulleride polymer.
Nonlinear induction detection of electron spin resonance
Applied Physics Letters, 2012
We present a new approach to the induction detection of electron spin resonance (ESR) signals exploiting the nonlinear properties of a superconducting resonator. Our experiments employ a yttrium barium copper oxide (YBCO) superconducting stripline microwave (MW) resonator integrated with a microbridge. A strong nonlinear response of the resonator is thermally activated in the microbridge when exceeding a threshold in the injected MW power. The responsivity factor characterizing the ESR-induced change in the system's output signal is about 100 times larger when operating the resonator near the instability threshold, compared to the value obtained in the linear regime of operation. Preliminary experimental results, together with a theoretical model of this phenomenon are presented. Under appropriate conditions nonlinear induction detection of ESR can potentially improve upon the current capabilities of conventional linear induction detection ESR.