Category not categories

High-contrast nonlinear spiral phase contrast imaging via four-wave mixing in atomic medium

WEI GAO,SANDAN WANG, JINPENG YUAN,LIRONGWANG,LIANTUAN XIAO, AND SUOTANG JIA

https://doi.org/10.1364/OE.572157

Journal 2025

Abstract: Nonlinearspiralphasecontrastimagingservesasapowerfultoolforhigh-performance image edge detection in optical imaging. Compared to conventional computer-based digital imaging methods, it oers numerous possibilities for optical image processing with superior speed, lower energy consumption, and high information capacity. Here, we experimentally demonstrate the high-contrast nonlinear spiral phase contrast imaging in a diamond-type atomic system. A pump vortex-ltered beam (780 nm) and a signal beam with object image (776 nm) simultaneously interact with Rb atomic medium. As a result, a 420 nm beam is generated via the nonlinear four-wave mixing process, carrying the edge information of asymmetric Arabic numeral patterns. The geometric patterns such as triangle, circle, and square are further utilized to validate the eectiv eness of nonlinear spiral phase contrast imaging. The high image contrast of ∼ 95.8%
is achieved owing to the stringent phase matching conditions via the atomic four-wave mixing process. Moreover, the directional nonlinear spiral phase contrast imaging of circle and square patterns at 420 nm are realized by employing a Laguerre-Gaussian composite vortex lter on the 780 nm pump beam. This work establishes a versatile platform for multi-wavelength optical image analysis and provides a robust foundation for developing optical information processing methods.

Fig. 1. (a) The diamond-type energy level conguration of Rb atoms. (b) Principle of the nonlinear SPC imaging via four-wave mixing in Rb vapor. (c) Sketch of the experimental setup. M, mirror; HWP, half-wave plate; PBS, polarization beam splitter; SLM, spatial light modulator; L, lens; A, aperture; BS, beam splitter; F, bandpass lter .

Rydberg electromagnetically induced85transparency of Rb vapor in Ar, Ne, and N gases

Bineet Dash,Nithiwadee Thaicharoen,Eric Paradis,Alisher Duspayev,and Georg Raithel

https://doi.org/10.1063/5.0237759

APL Quantum 2, 016132 (2025)

ABSTRACT
An experimental study on Rydberg electromagnetically induced transparency (EIT) in rubidium (Rb) vapor cells containing inert gases at pressures ≤5 Torr is reported. Using an inert-gas-free Rb vapor cell as a reference, we measure frequency shift and line broadening of the EIT spectra in Rb vapor cells with argon, neon, or nitrogen gases at pressures ranging from a few mTorr to 5 Torr. The results qualitatively 18 October 2025 11:50:48
agree with a pseudo-potential model that includes s-wave scattering between the Rydberg electron and the inert-gas atoms and the effect of polarization of the inert-gas atoms by the Rydberg atoms. Our results are important for establishing Rydberg-EIT as an all-optical and non-intrusive spectroscopic probe for eld diagnostics in low-pressure radio frequency discharges.

FIG. 1. (a) Energy levels of 85Rb used in our experiment. The probe laser (λp = 780 nm) is locked to the 5S1/2,
F = 3 ↔ 5P3/2, F′ = 4 resonance, and the coupling laser is scanned across the5P3/2 ↔ 36D5/2 transition.(b)Experimental setup. Some elements are omitted for simplicity.

Dual-Parameter Surface Plasmon Resonance Photonic Crystal Fiber Sensor for Simultaneous Magnetic Field and Temperature Detection with Potential SERS Applications

by Haoran Wang ,Shiwei Liu,Wenzhao Liu and Shuai Wang 

https://doi.org/10.3390/photonics12040355

This article belongs to the Special Issue Research, Development and Application of Raman Scattering Technology

Abstract

A high-sensitivity surface plasmon resonance (SPR) dual-parameter sensor based on photonic crystal fiber (PCF) is proposed for simultaneous measurement of magnetic field and temperature. The grooves on the right and upper sides of the PCF, serving as distinct detection channels, are filled with magnetic fluid and polydimethylsiloxane, respectively, enabling high-sensitivity detection of magnetic field and temperature. The structure parameters and sensing characteristics of the proposed sensor are investigated based on the finite element method. Numerical results indicate, within the wavelength range of 850–1050 nm, that the sensor achieves a high magnetic field sensitivity of 86 pm/Gs under x-polarization in the range of 100–600 Gs, and exhibits a temperature sensitivity of −2.63 nm/°C under y-polarization within the temperature range of 20–40 °C. Furthermore, the detection precision and applicability of the sensor in actual measurement applications could be further enhanced in the future by introducing surface-enhanced Raman scattering technology.

Figure . Schematic illustration of the cross-sectional view of the proposed dual-channel SPR-PCF sensor.

پیام تسلیت

سرکار خانم عابدی عزیز با نهایت تأسف و تأثر ضایعه در گذشت پدربزرگ گرامی‌تان را خدمت شما و خانواده محترم تسلیت عرض می‌کنیم. بقای عمر با عزت برای شما و همچنین رحمت واسعه برای آن مرحوم را از خداوند متعال خواستاریم

Cavity-enhanced solid-state nuclear spin gyroscope

Hanfeng Wang, Shuang Wu, Kurt Jacobs, Yuqin Duan, Dirk R Englund, Matthew E Trusheim

1. Massachusetts Institute of Technology, 50 Vassar Street, Cambridge, MA 02139, USA
2. Honda Research Institute USA, Inc., San Jose, CA 95134, USA
3. U.S. Army DEVCOM Army Research Laboratory, Adelphi, MD 20783, USA
4. Department of Physics, University of Massachusetts Boston, Boston, MA 02125, USA

Physical Review Letters 134 (18), 183603, 2025

https://doi.org/10.48550/arXiv.2502.01769

Solid-state quantum sensors based on ensembles of nitrogen-vacancy (NV) centers in diamond have emerged as powerful tools for precise sensing applications. Nuclear spin sensors are particularly well suited for applications requiring long coherence times, such as inertial sensing, but remain underexplored due to control complexity and limited optical readout efficiency. In this work, we propose cooperative cavity quantum electrodynamic (cQED) coupling to achieve efficient nuclear spin readout. Unlike previous cQED methods used to enhance electron spin readout, here we employ two-field interference in the NV hyperfine subspace to directly probe the nuclear spin transitions. We model the nuclear spin NV-cQED system (nNV-cQED) and observe several distinct regimes, including electromagnetically induced transparency, masing without inversion, and oscillatory behavior. We then evaluate the nNV-cQED system as an inertial sensor, indicating a rotation sensitivity improved by 3 orders of magnitude compared to previous solid-state spin demonstrations. Furthermore, we show that the NV electron spin can be simultaneously used as a comagnetometer, and the four crystallographic axes of NVs can be employed for vector resolution in a single nNV-cQED system. These results showcase the applications of two-field interference using the nNV-cQED platform, providing critical insights into the manipulation and control of quantum states in hybrid NV systems and unlocking new possibilities for high-performance quantum sensing.

FIG. 1. Two-eld interference in nNV-cQED. (a) Top: NV crystal structure. Bottom: diamond with NVs rotates with rate R = {Rx, Ry , Rz }. (b) NV energy level structure. The transition |1⟩ ↔ |e⟩ is coupled to the cavity mode for the cavity-enhanced readout. A driving eld Ω2 is applied between the spin-exchanging transition |2⟩ ↔ |e⟩. (c) Hybrid system with a microwave resonator and an NV spin ensemble. A green laser is applied to continuously polarize the NV spin to the |ms = 0⟩, and a detection loop is incorporated to measure the re ection signal from the resonator. (d) |α0|2 as a function of detuning ∆/κ within strong coupling regime. An EIT feature appears around the resonant frequency. (e) Top: Im(σ1e) as a function of Ω2. The EIT (MWI) regime features a negative (positive) Im(σ1e). Bottom: Time dynamics of Im(α). (f) α0 as a function of P and Ω2. The solid line indicates the perfect EIT condition. The boundary of the oscillation regime is marked as a white line.

congratulation to Our new paper in Journal of Optic

Temperature Dependent Random Laser Performance of Au@Cu and Cu@Au Core-Shell Nanoparticles in a Rhodamine 6G–PNIPAM Smart Polymer Matrix Medium

Mariam Kadhim Jawad, J. M. Jassim, S. F. Haddawi, S. M. Hamidi

Abstract:
This study aimed to investigate the temperature-dependent performance of random lasers using Rhodamine 6G (R6G) dye embedded in a thermoresponsive PNIPAM polymer matrix with Au, Cu, Au@Cu, and Cu@Au nanoparticles serving as scattering centers. At 25 °C, only fluorescence was observed due to the hydrophilic state of PNIPAM, resulting in high optical absorption and insufficient refractive index contrast for lasing. As temperature increased to 30–45 °C, PNIPAM became hydrophobic, enhancing index contrast and reducing absorption, which facilitated random lasing. Among the nanoparticles, Au showed the highest emission intensity (62618 a.u.) and narrowest FWHM (4.6 nm), followed by Cu@Au (59908 a.u., 5.3 nm), attributed to the strong plasmonic response of the Au shell. Conversely, Au@Cu and Cu exhibited weaker outputs due to higher damping and less effective plasmonic resonance. Temperature-dependent spectral analysis showed that Cu had the most pronounced bandwidth narrowing (7.5 nm to 3.4 nm), while Au@Cu demonstrated the highest intensity modulation (30913 a.u. to 65195 a.u.). A temperature-induced blue shift in peak emission was observed, most prominently in PNIPAM alone (6.2 nm), with smaller shifts in nanocomposite systems due to varied thermal coupling. These results highlight the pivotal role of PNIPAM’s thermal transition in controlling random laser behavior, offering new strategies for designing tunable or thermally stable laser systems.

Long-range hyperbolic polaritons on a non-hyperbolic crystal surface

Lu Liu, Langlang Xiong, Chongwu Wang, Yihua Bai, Weiliang Ma3, Yupeng Wang1, Peining Li, Guogang Li, Qi Jie Wang, Francisco J. Garcia-Vidal, Zhigao Dai & Guangwei Hu

Nature,Springer Nature

https://doi.org/10.1038/s41586-025-09288-1

Abstract:

Hybridized matter–photon excitations in hyperbolic crystals—anisotropic materials characterized by permittivity tensor components with opposite sign—have attracted substantial attention owing to their strong light–matter interactions in the form of hyperbolic polaritons. However, these phenomena have been restricted to hyperbolic crystals, whose optical responses are confined to fixed spectral regions and lack tunability, thereby limiting their broader applicability. Here we demonstrate the emergence of hyperbolic surface phonon polaritons in a non-hyperbolic yttrium vanadate (YVO₄) crystal. Using real-space nanoimaging combined with theoretical analyses, we visualize hyperbolic wavefronts of surface phonon polaritons on YVO₄ crystal surfaces within its non-hyperbolic frequency range, where the permittivity tensor components of the material have the same negative sign. Furthermore, by varying the temperature from room temperature to cryogenic levels, we realize in situ manipulation of polariton dispersions, enabling a topological transition from hyperbolic to canalization and eventually to the elliptic regime. This temperature-controlled dispersion engineering not only provides precise control over polariton topology but also modulates their wavelength and group velocity, showing remarkable sensitivity alongside low-loss, long-range propagation. These findings extend the realm of hyperbolic nano-optics by removing the reliance on hyperbolic crystals, unlocking opportunities for applications in negative refraction, superlensing, polaritonic chemistry ntegrated photonics and beyond.

congratulation to Our new paper in Journal of Pioneering Advances in Materials

High Signal to Noise Ratio in Miniaturized Atomic Cells by Frequency Modulation Spectroscopy Method

A. Mirazei, M. Sotoudeh, M. Asadolahsalmanpour, M. Mosleh, S. M. Hamidi

Magneto-plasmonic Lab, Laser and Plasma Research Institute, Shahid Beheshti University, Tehran, Iran.

DOI:10.48308/piadm.2025.105969

Abstract:

Miniaturized atomic vapor cells are emerging as essential components in various applications such as brain signal tracking, nitrogen-vacancy center magnetometry, and electric and magnetic field sensing. However, achieving a high signal-to-noise ratio (SNR) in these compact systems remains a key challenge, which can be addressed using selective spectroscopic techniques. In this study, we present a novel type of atomic vapor cell based on hot rubidium vapor, designed to enhance the spatial resolution of magnetometers. We also demonstrate the advantages of frequency modulation spectroscopy in improving spectral resolution. The cells are fabricated under a base pressure of 10⁻³ mbar and filled with nitrogen gas in a clean vacuum environment. The integration of these miniaturized cells with spectroscopic techniques enables their use in laser feedback loops to lock onto specific atomic transitions. This approach provides new possibilities for next-generation quantum technologies, including quantum sensors, atomic clocks, and quantum computing systems.

Schematic diagram of the experimental setup, with the circular cell shown in the inset

congratulation to Dear Dr Salmanpour for her PhD defense

congratulation to Our new paper in Journal of nanophotonics and nanostructure

Exploring the Interaction between Bloch Surface Waves and Atomic Hot Vapor: A Theoretical Perspective

A.Sohrabi, M. Asadolah Salmanpour, M. Mosleh, S. M. Hamidi,*

Abstract:

The miniaturization of atom-light interaction platforms is pivotal for the advancement of modern optical technologies, enabling significant improvements in sensing, communication, and quantum information processing. In this paper, we present a theoretical investigation onto the coupling of Bloch surface waves (BSWs) of one-dimensional photonic crystal with atomic hot vapor, emphasizing the miniaturization of atomic structures. These surface waves are known for their strong field confinement and high sensitivity to environmental changes which offer a promising avenue for enhancing light-matter interactions at reduced scales. Our findings highlight the potential of Bloch surface waves to enhance and control the localized density of states thus improving the resolution of atomic transition lines. This study underscores the importance of integrating Bloch surface waves with atomic hot vapor for developing next-generation miniaturized optical devices, which can lead to breakthroughs in precision metrology, high-resolution spectroscopy, and quantum technologies.