Probe Field Research Articles

Generation and enhancement of sum sideband in a magnon Kerr nonlinearity assisted optomechanical system

Abstract A theoretical scheme to enhance the sum sideband generation (SSG) via magnon Kerr nonlinearity assisted optomechanical system is proposed. In this scheme, the yttrium iron garnet sphere is placed within the cavity system and the frequency components are generated at the sum sideband through optomechanical nonlinear interaction and cavity-magnon linear coupling interaction. The results show that the efficiency of SSG can be enhanced by several orders of magnitude, and the gain in SSG efficiency also varies. The dependence of SSG on the system parameters, including the power of the control field, the frequency detuning of the probe fields and the coupling strengths between the optomechanical coupling and the cavity-magnon coupling is analyzed in detail. The change of SSG by varying the optomechanical coupling strength and cavity-magnon coupling strength is also investigated, and it is found that new matching conditions are generated. The enhanced SSG method may have potential application prospects in realizing the measurement of high-precision weak forces, quantum information processing and quantum-sensitive sensing.

Lineshape of Amplitude-Modulated Stimulated Raman Spectra

The amplitude modulation of a pump field and the phase-sensitive detection of a pump-induced intensity change of a probe field encompass a common practice in nonlinear spectroscopies to enhance the detection sensitivity. A drawback of this approach arises when the modulation frequency is comparable to the width of the spectral feature of interest, since the presence of sidebands in the amplitude-modulated pump field provides distortion to the observed spectral lineshape. This represents a problem when accurate measurements of spectral lineshapes and line positions are pursued, as recently happened in our group with the metrology of the Q(1) line in the 1-0 band of molecular hydrogen. The measurement was performed with a Stimulated Raman Scattering spectrometer that was calibrated, for the first time, against an optical frequency comb. In this work, we develop an analytical tool for nonlinear Stimulated Raman spectroscopies that allows us to precisely quantify spectral distortions arising from high-frequency amplitude modulation in one of the interacting fields. Once they are known, spectral distortions can be deconvolved from the measured spectra to retrieve unbiased data. The application of this tool to the measured spectra is discussed.

The Faraday Rotation Measure of the M87 Jet at 3.5 mm with ALMA

Faraday rotation is an important probe of the magnetic fields and magnetized plasma around active galactic nuclei jets. We present a Faraday rotation measure (RM) image of the M87 jet between 85.2 and 101.3 GHz with a resolution of ∼2″ with the Atacama Large Millimeter/submillimeter Array. We found that the RM of the M87 core is (4.5 ± 0.4) × 104 rad m−2 with a low linear polarization fraction of (0.88 ± 0.08)%. The spatial RM gradient in the M87 jet spans a wide range from ∼ −2 × 104 rad m−2 to ∼3 × 104 rad m−2 with a typical uncertainty of 0.3 × 104 rad m−2. A comparison with previous RM measurements of the core suggests that the Faraday rotation of the core may originate very close to the supermassive black hole. Both an internal origin and an external screen with a rapidly varying emitting source could be possible. As for the jet, the RM gradient indicates a helical configuration of the magnetic field that persists up to the kiloparsec scale. Combined with the kiloparsec-scale RM measurements at lower frequencies, we found that RM is frequency-dependent in the jet. One possible scenario to explain this dependence is that the kiloparsec-scale jet has a trumpet-like shape, and the jet coil unwinds near its end.

Coherent control of dressing interaction of sequential-doubly-dressed four-wave mixing

Abstract We investigate the coherent control of dressing interaction in four-wave mixing (FWM) in a Y-type four-level atomic system based on the dressed states theory. We study the density matrix equation acted by two dressing fields simultaneously governing FWM signal intensity and the eigenvalues under the dressed state formalism. It is shown that the peak position and intensity of Autler–Townes splitting both originate from the dressing interaction as the detuning of the probe field is scanned. Moreover, it is observed that the interaction could be controlled by the dressing fields. Such flexibly controlled nonlinear signal has potential applications in optical communication and quantum information processing.

Superposition of standing waves induced ultra high-resolution atom localization

Abstract In this study, we have theoretically demonstrated ultra-high resolution two-dimensional atom localization within a three-level $\lambda$-type atomic medium via superposition of asymmetric and symmetric standing wave fields. Our analysis provides understanding into the precise spatial localization of atomic positions at the atomic level, utilizing advanced theoretical approaches and principles of quantum mechanics. The dynamical behavior of a three-level atomic system is thoroughly analyzed using the density matrix formalism within the realm of quantum mechanics. A theoretical approach is constructed to describe the interaction between the system and external fields, specifically a control field and a probe field. The absorption spectrum of the probe field is thoroughly examined to clarify the spatial
localization of the atom within the proposed configuration. We have theoretically investigated that symmetric and asymmetric superposition phenomena significantly influence the localized peaks within a two-dimensional spatial domain. Specifically, the emergence of one and two sharp localized peaks has been observed within a region of one wavelength domain. We observed notable influences of the intensity of the control field, probe field detuning, and decay rates on atom localization. Ultimately, we have achieved an unprecedented level of ultra-high resolution and precision in localizing an atom within an area smaller than λ/35×λ/35. These findings hold promise for potential applications in domains such as Bose-Einstein condensation, nanolithography, laser cooling, trapping of neutral atoms, and the measurement of center-of-mass wave-functions.

Giant lateral shift in single mode cavity containing four-level sodium atomic medium

Abstract In this paper, a four-level sodium atomic medium coupled to a single-mode cavity is used to investigate the Goos-Ha¨nchen (GH) shift. Using the collective phase of the control fields and intensity of Rabi oscillation, the positive as well as negative GH-shift in transmission and reflection beams are examined. In the transmission beam, a maximum GH-shift of ±6λ is observed. Furthermore, GH-shift in both reflection and transmission beams in a four-level sodium atomic medium is significantly enhanced by photon number density as well as by the cavity coupling strength. By varying the collective phase of the control fields and the probe field frequency, GH-shift in reflection exhibits a maximum value of ±2λ. Our findings may open up significant applications in micro-optics, sensors, photonic crystals and nano-processor technology.

Circumferential Crack Detection in Ultra-High-Pressure Tubular Reactors with Pulsed Eddy Current Testing.

Ultra-high-pressure tubular reactors are crucial pieces of equipment for polyethylene production. Long-term operation under high temperature, high pressure, and other extremely harsh conditions can lead to various defects, with circumferential cracks posing a major safety risk. Detecting cracks is challenging, particularly when they are under a protective layer of a certain thickness. This study designed a pulsed eddy current differential probe to detect circumferential cracks in ultra-high-pressure tubular reactors, with the lift-off distance acting as a protective layer. Detection models for traditional cylindrical and semi-circular excitation differential probes were established using finite element simulations. Corresponding experiments under different lift-off conditions were carried out, and the model's accuracy was verified by the consistency between the simulation results and experimental data. The distribution of the eddy current field under different conditions and the disturbances caused by cracks at various positions to the detection signal were then calculated in the simulations. The simulation results showed that the cracks significantly disturbed the eddy current field of the semi-circular excitation differential probe compared with that of the traditional cylindrical probe. The designed differential probe effectively detected circumferential cracks of specific lengths and depths using the difference in the voltage signals. The experimental results were in agreement with the simulation results, showing that the designed probe could effectively detect 20 mm-long circumferential cracks at a lift-off of 60 mm. The experimental results also show that the probe's detection coverage area in the axial direction varied with the lift-off height. The probe design and findings are valuable for detecting cracks in ultra-high-pressure tubular reactors with protective layers.

Three-cavity system with multiple magnomechanically induced transparency

This paper presents the characteristics of a weak probe field in a three-connected cavity system. In this system, a microwave cavity contains a yittrium iron garnet sphere that is driven by a strong pump and a weak probe optical fields, and the magnon is driven by a weak microwave source. The other two cavities are empty and are coupled to the first cavity with specific coupling strengths. This setup leads to the observation of multiple magnomechanically induced transparency phenomena by varying quantum parameters g ma, g mb, and the coupling strengths between cavities J 1 and J 2. The study of these phenomena in the three coupled cavities can potentially contribute to advancements in quantum transduction and future technologies.

Publisher Correction: Rydberg states of alkali atoms in atomic vapour as SI-traceable field probes and communications receivers

Publisher Correction: Rydberg states of alkali atoms in atomic vapour as SI-traceable field probes and communications receivers

Phase-modulation-induced reconfigurable rotating photonic lattices in atomic vapors.

We propose a method to prepare optically induced rotating hexagonal and honey-comb photonic lattices by employing the phase modulated three-beam interference in atomic vapors with electromagnetically induced transparency. The phase differences among the three beams are dynamically elaborated to synthesize the circular motion (in transverse dimensions) of waveguides in the photonic lattices. Further, we verify this model experimentally in the case of low-speed modulation. A weak Gaussian probe field is sent into the constructed helical photonic lattices to image their structures under electromagnetically induced transparency (EIT). The motion trajectories of the sites on the discretized output patterns exhibit repeated circles, advocating the formation of rotating lattices. By introducing phase modulations to involved beams, we provide a continent way for producing transverse motions in waveguide arrays with reconfigurability in rotational direction, radius, and speed. This work looks forward to promising applications in topological photonics with great popularity.

Custom integration of a magnetic-field monitoring system into a 32-channel MRI head coil.

Customizing a Siemens 32-channel coil for use in a Philips 3T MRI system with incorporated magnetic field probes for collecting high-quality MRI and magnetic-field monitoring data concurrently. The development process of the custom coil involved several (iterative) phases. Standard temporal SNR and B1 + data were collected with the 32-channel Siemens and for reference the 32-channel/8-channel Philips head coils before and afterthe custom coil was made compatible with the 3T Philips Achieva system, and magnetic field probes were installed into it along with ancillary electronics around it. Quality assurance tests were conducted in each of the build phases to ensure that the modifications did not affect MRI or field-monitoring data negatively. To test the finished custom coil, we collected high angular resolution diffusion imaging (HARDI) datasets on a spherical silicon oil phantom both with and without concurrent field monitoring and a 32-channel Philips coil without concurrent field monitoring, where the latter two served as reference scans to assess the improved performance of the custom coil with field monitoring. Similar HARDI-MRI data were also collected in vivo with the finished custom coil together with field monitoring data. The custom coil provided excellent temporal SNR especially at the edges where cortical gray matter is expected. When using concurrent field monitoring in HARDI acquisitions, the custom coil alleviated ghosting artifacts in phantom data and provided in vivo images with 1.4-mm isotropic resolution. The custom MRI coil with integrated magnetic-field monitoring probes provided improved imaging performance.

Electromagnetically induced grating via amplitude and phase modulations in a three-level V-type atomic medium

Abstract A probe laser beam can be completely absorbed in an atomic resonance frequency region, however, if a coupling laser beam is further applied to the atom, the atomic medium can exhibit electromagnetically induced transparency (EIT), i.e, the probe beam can be completely transmitted through the atomic medium. Thus, if the coupling beam is a standing wave field with nodes and antinodes, it will cause in space a periodic modulation of the transmitted spectrum of the probe field. This means that the probe field propagates through the atomic medium just as it passes through a diffraction grating which is called electromagnetically induced grating (EIG). Based on amplitude or phase modulation of transmission function, the absorption grating or the phase grating can be formed, respectively. In this work, based on controllable absorption and dispersion properties of a three-level V-type atomic system, we study the control of the absorption grating and the phase grating with respect to the intensity and the frequency of the laser fields. The absorption diffraction pattern at the two-photon resonance is obtained, while the phase diffraction pattern appears when there is a frequency shift of either the coupling frequency or the probe frequency compared to the corresponding atomic resonance frequency. By adjusting the coupling or/and probe laser frequency, the absorption grating can be converted into the phase grating and the high-order diffraction efficiency can also be improved.

Optical frequency combs and chaos in a hybrid atom–cavity optomagnonical system via the synergy of double-probe fields

We theoretically investigate the modulation of optical frequency combs and chaos by the synergy of double-probe fields in the hybrid atom–cavity optomagnonical system consisting of a yttrium iron garnet sphere, a two-level atom, and a tapered fiber. Our results show that in the case of a single-probe field, the atom-optical mode coupling strength and amplitude strength of the probe field can effectively modify the tooth spacing (from one to one-half tooth spacing) of the optical frequency combs, as well as the entry or withdrawal of chaos. In a chaotic region, the relative phases between the control and probe fields can also be adjusted to withdraw chaotic motion. Moreover, we demonstrate the generation of hybridized fraction-order frequency combs via the synergy of double-probe fields, which is caused by the sum and difference frequency effects of sidebands. Interestingly, it is found that through the synergy of the double-probe fields, the system can enter a chaotic state under lower applied field intensity, which is modulated by the amplitude strengths and relative phases of the dual probe fields. In addition to providing insight into the characteristics of optical frequency combs and chaos in the hybrid atom–cavity optomagnonical system, our research may offer a new perspective for the development of precision measurements and secret information processing.

Transfer of nonclassical correlations between bosonic field and atomic ensemble through electromagnetically induced transparency

Dark state polariton, as an important concept in the mechanism of electromagnetic induced transparency (EIT), can map the state of bosonic fields to atomic ensembles. To reflect the mapping ability of dark state polariton, we choose the odd and even bosonic coherent states as the probe field in EIT process, and employ spin squeezing, entanglement, and quantum correlation to characterize nonclassical correlations of atomic ensembles during the manipulation of the driving field. It is shown that the differences between the odd and even coherent states are comprehensively reflected in the three characterizations of nonclassical correlations generated through dark state polaritons. The even bosonic coherent states can perfectly transfer bosonic squeezing into atomic ensembles, resulting in spin squeezing. Although the odd bosonic coherent states cannot induce the spin squeezing, they have an advantage over the even bosonic coherent states in generating quantum entanglement and quantum correlations. Furthermore, we demonstrate that atomic ensembles can achieve significant spin squeezing with squeezing degree ∝ 1/N 2/3 through the one-axis twisting (OAT) model and two-axis twisting (TAT) model under the large N limit with the low excitation conditions, and the EIT mechanism was used to transfer the generated spin squeezing to the bosonic field, providing a feasible strategy for obtaining significant bosonic squeezing.

Determining the relationship between mobile phone network signal strength and radiofrequency electromagnetic field exposure: protocol and pilot study to derive conversion functions

Mobile phones continuously monitor and evaluate indicators of the received signal strengths from surrounding base stations to optimise wireless services. These signal strength indicators (SSIs) offer the potential for assessing radiofrequency electromagnetic field (RF-EMF) exposure on a population scale, as they can be related to exposure from both base stations and handset devices. Within the ETAIN (Exposure To electromAgnetic fields and plaNetary health) project, an open-access RF-EMF exposure app for smartphones, named "5G Scientist Monitor”, has been developed using citizen science. This paper delineates a measurement protocol for deriving formulas to convert the app SSIs into electric field values to estimate RF-EMF exposure. It presents pilot study results from measurements taken at four locations in Lyon, France (FR), and 14 locations in the Netherlands (NL), using three different phone models and the most common network providers in each country. The measurements were conducted while executing different usage scenarios, such as calls or data transmission. The exposimeter ExpoM-RF4 and on-body electric field probes were used to measure exposure from far-field sources and the handset, respectively. Two-minute aggregates were considered the sample unit for analyses (n=891 in NL and n=395 in FR). Regression analyses showed a positive log-linear relationship between Long Term Evolution (LTE) SSIs and far-field RF-EMF exposure when aggregating data by location (coefficients for the normalised RSSI: 0.91 [95% CI: 0.55 - 1.28] in FR, 1.09 [95% CI: 0.96 - 1.22] in NL). Negative log-linear trends were observed for handset-related RF-EMF exposure at the ear (-0.31 [95% CI: -0.46 - -0.16]) and chest (-0.20 [95% CI: -0.37 - -0.03]) during data transmission scenarios. These results demonstrate that the 5G-Scientist-Monitor app can be implemented for smartphone-based RF-EMF estimation. However, uncertainties in individual measurement points highlight the need for further data collection and analysis to improve the accuracy of exposure estimates.

Tunable multicolor optomechanically induced transparency and slow-fast light in hybrid electro-optomechanical system

Abstract We investigate the tunable multicolor optomechanically induced transparency and the effect of slow/fast light in a hybrid electro-optomechanical system, in which a degenerate optical parametric amplifier (OPA) and a Λ − type three-level atomic ensemble are placed in a optical cavity with two oscillator modes. The system is driven by a strong pump field and a weak probe field, respectively. Multicolor transparency windows appear in the output field under the atom-photon-OPA-phonon-phonon coherent interaction. And the position and width of the transparent port of the output field can be manipulated by properly modifying the different parameters of the subsystem. We also research the slow/fast light effect related to phase and group delay in the probe field. Our proposal provides a great flexibility for phonon storage and has some potential applications in quantum information processing.

Rydberg states of alkali atoms in atomic vapour as SI-traceable field probes and communications receivers

Rydberg states of alkali atoms in atomic vapour as SI-traceable field probes and communications receivers

Efficient control of high-precision three-dimensional atom localization via probe absorption in a five-level phase-coherent atomic system

We propose a new scheme for high-precision three-dimensional (3D) atom localization by observing the spatially modulated absorption of a weak probe field operating in a partially closed-loop dependent five-level atomic system. Different spatial structures of localization patterns are presented by controlling the Rabi frequency, detuning, and field-induced collective phase-coherence with a variety of superposed standing wave field configurations. Our results highlight that 100% detection probability of atom is possible in the present model in many ways with high precision measurement of spatial absorption. It has been shown that, in the presence of standing wave fields, position information of the atom with maximum detection probability can be efficiently controlled by employing the travelling-wave field in the system. In the present work, we note that the maximum detection probability of the atom is attainable with the limit of spatial resolution better than λ/50. The efficacy of the present model is to find its application in atom nanolithography and atom-imaging having importance in quantum information processing.

Effect of Alkyl Chain Length on Room-Temperature Phosphorescent Probes for Mitochondria-Targeted Imaging.

Room temperature phosphorescent (RTP) probes have significant advantages in the field of cellular imaging, as their long lifetimes can prevent interference from the spontaneous fluorescence of organisms. Persulfurated arenes are a typical RTP molecular parent nucleus. However, most of the applied research on them is concentrated in anti-counterfeiting, and relatively few are applied in bioimaging. The molecular structure and structure-property relationship of them applied in bioimaging are still in the exploration stage. In this work, we have designed and synthesized a series of RTP probes with long alkyl chains, all of which can be targeted to mitochondria with good water solubility for mitochondria-targeted imaging. Further, we investigated the effect of alkyl chains on the luminescence properties of these probes, and found that the moderate length of alkyl chains can realize the enhancement of phosphorescence intensity. We believe this finding is of guiding significance for the design of molecular structures in the field of RTP probes.

Coherent manipulation of giant birefringent Goos–Hänchen shifts by compton scattering using chiral atomic medium

A four level chiral medium is considered to analyze and investigate theoretically the reflection/transmission coefficients of right circularly polarized (RCP) beam and left circularly polarized (LCP) beam as well as their corresponding GH-shifts under the effect of compton scattering. Density matrix formalism is used for calculation of electric and magnetic probe fields coherence. The polarization and magnetization are calculated from probes coherence terms in the chiral medium. The electric and magnetic susceptibilities as well as chiral coefficients are related with polarization and magnetization. The refractive indices of RCP and LCP beams under compton scattering effect is modified from the electric/magnetic susceptibilities, chiral coefficients, mass and charge of electron as well as compton scattering angle. The giant positive and negative birefringent Goos–Hänchen (GH) shifts in reflection and transmission beams are investigated in this manuscript under Compton scattering effect. The RCP and LCP beams obey the normalization condition |R(+,-)|+|T(+,-)|=1\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$|R^{(+,-)}|+|T^{(+,-)}|=1$$\\end{document} at the interface of a lossy chiral medium of |A(+,-)|≃0\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$|A^{(+,-)}|\\simeq 0$$\\end{document} and a thin sheet of balsa wood under the effect of compton scattering angle, incident angle, probe field detuning, control field Rabi frequency, phases of electric and magnetic fields and phase of superposition states. Significant positive/negative giant GH-shifts in reflection and transmission beams are investigated. The results show potential applications in modification of cloaking devices, image coding, polarizing filters and LCD displays.