Multi-photon transitions and Rabi resonance in continuous wave EPR

Saǐko, A. P.; Fedaruk, R.; Markevich, S. A.

doi:10.1016/j.jmr.2015.07.013

Cited by 25 publications

(22 citation statements)

References 37 publications

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“…The amplitude of the 100 kHz magnetic field modulation was 0.01 mT. The absorption CW EPR spectrum is usually obtained by phase-sensitive detection at the frequency, rf , of the magnetic field modulation, which selects the first-harmonic component of the spin response, even though higher harmonics are present [22][23][24]. In-phase and 90° out-of-phase (or simply out-of-phase) components refer to the phase of the EPR signal relative to that of the magnetic field modulation.…”

Section: Methodsmentioning

confidence: 99%

Identification of a Slowly Relaxing Paramagnetic Center in Graphene Oxide

et al. 2018

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We demonstrate the existence of two types of paramagnetic centers in a pure graphene oxide. Saturation features of the electron paramagnetic resonance (EPR) spectrum in the temperature range of 4.2-300 K reveal that one of these centers has the spin-lattice relaxation time longer than 1.6 μs at room temperature. The spectrum of these centers consists of a central line and two satellite lines. The satellite lines result from the forbidden transitions in the hyperfine structure induced by protons in the vicinity of the slowly relaxing centers. The observability of the satellites can be used as a characteristic signature of graphene oxide purity. Since the number of slowly relaxing centers is reduced during chemical reduction of graphene oxide, this type of centers can be attributed to the isolated unfunctionalized carbons in the highly functionalized regions of GO. The second type of paramagnetic centers has shorter relaxation times and dominates in the reduced graphene oxide.

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Section: Methodsmentioning

confidence: 99%

Identification of a Slowly Relaxing Paramagnetic Center in Graphene Oxide

et al. 2018

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“…Concatenated continuous driving has been explored in several works [17,18,[23][24][25][26][27][28][29][30][31][32], typically in the context of protecting a qubit against decoherence. Here we focus on the simplest scheme, where only a second modulation is applied to the first driving field.…”

Section: Appendix A: Concatenated Continuous Drivingmentioning

confidence: 99%

“…To overcome the challenges associated with the driving power needed to reach the regime beyond the RWA, we use concatenated continuous driving (CCD). CCD is a continuous dynamical decoupling technique with multiple resonant modulated fields and has been studied before in the context of qubit coherence protection [17,18,[23][24][25][26][27][28][29][30][31][32]. Here we use the CCD technique to engineer an effective static field along the x direction and a single-tone AC field in the rotating frame (interaction picture) [24], as we show in Sec.…”

Section: Introductionmentioning

confidence: 99%

Observation of the high-order Mollow triplet by quantum mode control with concatenated continuous driving

2021

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The Mollow triplet is a fundamental signature of quantum optics and has been observed in numerous quantum systems. Although it arises in the "strong driving" regime of the quantized field, where the atoms undergo coherent oscillations, it can be typically analyzed within the rotating wave approximation. Here we report the first observation of high-order effects in the Mollow triplet structure due to strong driving. In experiments, we explore the regime beyond the rotating wave approximation using concatenated continuous driving that has less stringent requirements on the driving field power. We are then able to reveal additional transition frequencies, shifts in energy levels, and corrections to the transition amplitudes. In particular, we find that these amplitudes are more sensitive to high-order effects than the frequency shifts and that they still require an accurate determination in order to achieve high-fidelity quantum control. The experimental results are validated by Floquet theory, which enables the precise numerical simulation of the evolution and further provides an analytical form for an effective Hamiltonian that approximately predicts the spin dynamics beyond the rotating wave approximation.

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“…Multiphoton excitation has been described for NMR and EPR . For NMR, two‐photon excitation has been used to permit simultaneous RF transmit and receive, as the transmitted RF has distinctive frequency from received RF tuned at the Larmor frequency.…”

Section: Introductionmentioning

confidence: 99%

Multiphoton magnetic resonance in imaging: A classical description and implementation

Han

2020

Magnetic Resonance in Med

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Funding information UC BerkeleyPurpose: To develop a classical geometric interpretation of multiphoton excitation and apply it to MRI. To investigate ways in which multiphoton excitation can enable novel imaging techniques. Theory and Methods: We present a fully geometric view of multiphoton excitation by taking a particular rotating frame transformation. In this rotating frame, we find that multiphoton excitations appear just like single-photon excitations again, and therefore, we can readily generalize concepts already explored in standard singlephoton excitation. With a homebuilt low frequency coil, we execute a standard slice selective pulse sequence with all of its excitations replaced by their equivalent twophoton versions. In the case of no extra hardware, we use oscillating gradients as a source of extra photons for excitation. Finally, with the multiphoton interpretation of oscillating gradients, we present a novel way to transform a standard slice selective adiabatic inversion pulse into a multiband version without modifying the RF pulse itself. The addition of oscillating gradients creates multiphoton resonances at multiple spatial locations and allows for adiabatic inversions at each location. Results: With Bloch-Siegert shift corrections, analytical multiphoton excitation expressions match with Bloch equation simulations. Two-photon gradient-echo images of a lemon and a pork rib match with their single-photon counterparts.Frequency-offset RF combined with oscillating gradients generate excitation where the RF alone does not. Conclusion: The multiphoton interpretation presents new flexibilities for imaging.Excitation needs not be bound to the Larmor frequency, which opens doors to RF pulse design beyond the usual filter design and the potential for further imaging innovations. K E Y W O R D Sadiabatic, Bloch-Siegert shift, multiband, multiphoton, selective excitation, two-photon ORCID Victor Han https://orcid.org/0000-0003-3093-2549 Chunlei Liu https://orcid.org/0000-0001-8816-4832

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Multi-photon transitions and Rabi resonance in continuous wave EPR

Cited by 25 publications

References 37 publications

Identification of a Slowly Relaxing Paramagnetic Center in Graphene Oxide

Identification of a Slowly Relaxing Paramagnetic Center in Graphene Oxide

Observation of the high-order Mollow triplet by quantum mode control with concatenated continuous driving

Multiphoton magnetic resonance in imaging: A classical description and implementation

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