Current sensor based on diamond nitrogen-vacancy color center

High precision current measurement is very important for the calibration of various high-precision equipment and the measurement of other precision detection fields.A new current sensor based on diamond nitrogen-vacancy(NV)color center magnetic measurement method is proposed to realize the accurate measurement of current.This new current method can greatly improve the accuracy of current measurement.Experiments show that the linearity of the current sensor based on diamond NV color center can reach up to 33 ppm,which is superior to other current sensors and solves the problem of low linearity.When the range of input current is 5-40 A,the absolute error of the calculated current is less than 51μA,and the relative error is 2.42×10^(-6) at 40 A.Combined with the research content and results of the experiment,the application of the current sensor in the field of current precision measurement is prospected.

Color center and radiation center in Lu_2SiO_5:Ce crystal

Radiation damage of Lu2SiO5：Ce （LSO：Ce） crystals was investigated through intense UV light. An absorption band at 435 nm was observed in the transmission spectrum of the damaged LSO：Ce crystal, similar to that of absorption band caused by gamma ray irradiation. GDMS analysis for LSO：Ce crystals revealed the existence of impurities, such as Yb in the crystals. The impurities might be responsible for the optical absorption of the color center and the radiation center.

Effect of radiation-induced color centers absorption in optical fibers on fiber optic gyroscope for space application

The effects of color centers＇ absorption on fibers and interferometric fiber optical gyroscopes（IFOGs） are studied in the paper. The irradiation induced attenuation（RIA） spectra of three types of polarization-maintaining fibers（PMFs）, i.e.,P-doped, Ge-doped, and pure silica, irradiated at 100 Gy and 1000 Gy are measured in a wavelength range from 1100 nm to1600 nm and decomposed according to the Gaussian model. The relationship of the color centers absorption intensity with radiation dose is investigated based on a power model. Furthermore, the effects of all color centers＇ absorption on RIA and mean wavelength shifts（MWS） at 1300 nm and 1550 nm are discussed respectively. Finally, the random walk coefficient（RWC） degradation induced from RIA and the scale factor error induced by MWS of the IFOG are simulated and tested at a wavelength of 1300 nm. This research will contribute to the applications of the fibers in radiation environments.

Dependence of nitrogen vacancy color centers on nitrogen concentration in synthetic diamond

Crystallization of diamond with different nitrogen concentrations was carried out with a FeNiCo-C system at pressure of 6.5 GPa.As the nitrogen concentration in diamond increased,the color of the synthesized diamond crystals changed from colorless to yellow and finally to atrovirens(a dark green).All the Raman peaks for the obtained crystals were located at about 1330 cm^(-1)and contained only the sp^(3)hybrid diamond phase.Based on Fourier transform infrared results,the nitrogen concentration of the colorless diamond was<1 ppm and absorption peaks corresponding to nitrogen impurities were not detected.However,the C-center nitrogen concentration of the atrovirens diamond reached 1030 ppm and the value of A-center nitrogen was approximately 180 ppm with a characteristic absorption peak at 1282 cm^(-1).Furthermore,neither the NV^(0)nor the NV^(-)optical color center existed in diamond crystal with nitrogen impurities of less than 1 ppm by photoluminescence measurement.However,Ni-related centers located at 695 nm and 793.6 nm were observed in colorless diamond.The NE8 color center at 793.6 nm has more potential for application than the common NV centers.NV^(0)and NV^(-)optical color centers coexist in diamond without any additives in the synthesis system.Importantly,only the NV^(-)color center was noticed in diamond with a higher nitrogen concentration,which maximized optimization of the NV^(-)/NV^(0)ratio in the diamond structure.This study has provided a new way to prepare diamond containing only NV^(-)optical color centers.

Single-channel vector magnetic information detection method based on diamond NV color center

A method of detecting the single channel triaxial magnetic field information based on diamond nitrogen-vacancy(NV)color center is introduced.Firstly,the incident angle of the bias magnetic field which can achieve the equal frequency difference optically-detected magnetic resonance(ODMR)spectrum of diamond NV color center is calculated theoretically,and the triaxial magnetic information solution model is also constructed.Secondly,the microwave time-controlled circuit module is designed to generate equal timing and equal frequency difference microwave pulse signals in one channel.Combining with the optical detection magnetic resonance technology,the purpose of sequentially locking and detecting the four formant signals on one side of the diamond NV color center(m_(s)=-1 state signal)is achieved,and the vector magnetic field information detection is accomplished by combining the triaxial magnetic information solution model.The system can obtain magnetic field detection in a range of 0 mT-0.82 mT.The system's magnetic noise sensitivity is 14.2 nT/Hz^(1/2),and the deviation angle errors of magnetic field detectionθ_(x) andθ_(y) are 1.3° and 8.2° respectively.

Non-destructive Testing Method for Crack Based on Diamond Nitrogen-vacancy Color Center

Magnetic field measurement plays an extremely important role in material science,electronic en-gineering,power system and even industrial fields.In particular,magnetic field measurement provides a safe and reliable tool for industrial non-destructive testing.The sensitivity of magnetic field measurement deter-mines the highest level of detection.The diamond nitrogen-vacancy(NV)color center is a new type of quan-tum sensor developed in recent years.The external magnetic field will cause Zeeman splitting of the ground state energy level of the diamond NV color center.Optical detection magnetic resonance(ODMR),using a mi-crowave source and a lock-in amplifier to detect the resonant frequency of the NV color center,and finally the change of the resonant frequency can accurately calculate the size of the external magnetic field and the sensi-tivity of the external magnetic field change.In the experiment,a diamond containing a high concentration of NV color centers is coupled with an optical fiber to realize the preparation of a magnetic field scanning probe.Then,the surface cracks of the magnetized iron plate weld are scanned,and the scanning results are drawn into a two-dimensional magnetic force distribution map,according to the magnetic field gradient change of the magnetic force distribution map,the position and size of the crack can be judged very accurately,which pro-vides a very effective diagnostic tool for industrial safety.

Single‑Photon Sources Based on Novel Color Centers in Silicon Carbide P–I–N Diodes: Combining Theory and Experiment

Point defects in the crystal lattice of SiC,known as color centers,have recently emerged as one of the most promising single-photon emitters for non-classical light sources.However,the search for the best color center that satisfies all the requirements of practical applications has only just begun.Many color centers in SiC have been recently discovered but not yet identified.Therefore,it is extremely challenging to understand their optoelectronic properties and evaluate their potential for use in practical single-photon sources.Here,we present a theoretical approach that explains the experiments on single-photon electroluminescence(SPEL)of novel color centers in SiC p-i-n diodes and gives the possibility to engineer highly efficient single-photon emitting diodes based on them.Moreover,we develop a novel method of determining the electron and hole capture cross sections by the color center from experimental measurements of the SPEL rate and second-order coherence.Unlike other methods,the developed approach uses the experimental results at the single defect level that can be easily obtained as soon as a single-color center is identified in the i-type region of the SiC p-i-n diode.

Silicon Vacancy Color Centers in 6H-SiC Fabricated by Femtosecond Laser Direct Writing

As a single photon source,silicon vacancy(V_(Si))centers in wide bandgap semiconductor silicon carbide(SiC)are expected to be used in quantum technology as spin qubits to participate in quantum sensing and quantum computing.Simultaneously,the new direct femtosecond(fs)laser writing technology has been successfully applied to preparing V_(Si)s in SiC.In this study,6H-SiC,which has been less studied,was used as the processed material.V_(Si) center arrays were formed on the 6H-SiC surface using a 1030-nm-wavelength fs pulsed laser.The surface was characterized by white light microscopy,atomic force microscopy,and confocal photoluminescence(PL)/Raman spectrometry.The effect of fs laser energy,vector polarization,pulse number,and repetition rate on 6H-SiC V_(Si) defect preparation was analyzed by measuring the V_(Si) PL signal at 785-nm laser excitation.The results show that fs laser energy and pulse number greatly influence the preparation of the color center,which plays a key role in optimizing the yield of V_(Si)s prepared by fs laser nanomachining.

Radiation induced color centers in cerium-doped and cerium-free multicomponent silicate glasses

The effect of doped cerium on the radiation-resistance behavior of silicate glass was investigated in our work. The ultraviolet-visible absorption spectra and electron paramagnetic resonance（EPR） spectra were obtained after the cerium-rich and cerium-free multicomponent silicate glasses（K509 and K9） were irradiated by gamma rays with a dose range from 10 to 1000 kGy. The results showed that E’ center, oxygen deficient center（ODC） and non-bridging oxygen hole center（HC1 and HC2） were induced in K9 and K509 glasses after radiation. The concentrations of all color centers presented an exponential growth with the increase of the gamma dose. Moreover, the concentration of HC1 and HC2 in cerium-doped K509 glass was much lower than that in cerium-free K9 glass at the same dose of radiation, which could be attributed to the following mechanism： Ce3＋ ions capturing holes then forming Ce3＋＋ centers inhibited the formation of hole trapped color centers（HC1 and HC2） and Ce4＋ ions capturing electrons to form Ce3＋ centers suppressed the formation of electron trapped color centers like E’ center.

Novel color center platforms enabling fundamental scientific discovery

Color centers are versatile systems that generate quantum light,sense magnetic fields and produce spin-photon entanglement.We review how these properties have pushed the limits of fundamental knowledge in a variety of scientific disciplines,from rejecting local-realistic theories to sensing superconducting phase transitions.In the light of recent progress in material processing and device fabrication,we identify new opportunities for interdisciplinary fundamental discoveries in physics and geochemistry.

Refractive Index Change and Color Center Formation in LiYF_4 Crystal Induced by a Femtosecond Laser

The refractive index change and color centers formation in LiYF4 crystal at room temperature are induced by a femtosecond laser irradiation. A mechanism for refractive index change and color centers formation is proposed.

Color centers in wide-bandgap semiconductors for subdiffraction imaging:a review

Solid-state atomic-sized color centers in wide-band-gap semiconductors,such as diamond,silicon carbide,and hexagonal boron nitride,are important platforms for quantum technologies,specifically for single-photon sources and quantum sensing.One of the emerging applications of these quantum emitters is subdiffraction imaging.This capability is provided by the specific photophysical properties of color centers,such as high dipole moments,photostability,and a variety of spectral ranges of the emitters with associated optical and microwave control of their quantum states.We review applications of color centers in traditional super-resolution microscopy and quantum imaging methods,and compare relative performance.The current state and perspectives of their applications in biomedical,chemistry,and material science imaging are outlined.

Photoluminescence and Raman Spectroscopy Study on Color Centers of Helium Ion-Implanted 4H-SiC

Color centers in silicon carbide(SiC)are promising candidates for quantum technologies.However,the richness of the polytype and defect configuration of SiC makes the accurate control of the types and position of defects in SiC still challenging.In this study,helium ion-implanted 4H-SiC was characterized by atomic force microscopy(AFM),confocal photoluminescence(PL),and confocal Raman spectroscopy at room temperature.PL signals of silicon vacancy were found and analyzed using 638-nm and 785-nm laser excitation by means of depth profiling and SWIFT mapping.Lattice defects(C-C bond)were detected by continuous laser excitation at 532 nm and 638 nm,respectively.PL/Raman depth profiling was helpful in revealing the three-dimensional distribution of produced defects.Differences in the depth profiling results and SRIM simulation results were explained by considering the depth resolution of the confocal measurement setup,helium bubbles,as well as swelling.

Determination of color centers in CaF_2 crystals by multiple gamma-ray irradiations

Color centers of CaF2 crystals subjected to three high-dose gamma-ray irradiation treatments were studied. Three absorption bands at 349, 409 and 478 nm are ascribed to the F interstitials through the variation in difference additional absorption values. The transformation of interstitial F atoms to F ions (Fi-) is demonstrated using data with increasing radiation dose. The decrease in the 600 nm absorption band and the occurrence of the 580 nm band correspond to F2+ center conversion to F center. The complex (F^--Fi0 ) might be associated with the 962 and 1196 nm bands.

New color centers and luminescence of BaFI: Eu^(2+)

MANY publications have appeared on the photostimulated luminescence (PSL) of alkalineearth mixhalides. Color centers play a very important role in the PSL and X-ray storage imag-ing processes. The F centers, V centers and oxygen-related centers in this kind ofcrystals have been investigated. All these reports provide some useful information to the PSLmechanism and thus improve the practical applications of these materials. New color centers

GeV重离子束辐照LiF引起的晶体内部结构改变

高能强流重离子束入射到固体物质中,沿飞行路径的离子能量沉积密度将改变宏观靶物质的温度和压强等,并可能在高压高密条件下产生新的材料缺陷.本文利用兰州重离子加速器装置HIRFL-CSR引出的能量为264 MeV/u的Xe^(36+)离子束,入射到LiF晶体靶物质中,在线测量了LiF的发射光谱,观测到沿离子路径的晶体颜色变化.通过解离方法取得了不同位置处的X射线衍射(X-ray Diffraction)与X射线光电子能谱结果,显示在Xe离子的布拉格峰区域出现了LiF_(3)(LiF+F_(2))结构相,讨论了新的结构缺陷的产生与重离子束能量沉积密度间可能的相关性.这为离子束驱动的高能量密度物理的能量沉积过程提供了一定参考.

金刚石色心调控及光学谐振器的研究进展

金刚石因其优异的光学特性和色心发射器而被应用于光子器件领域。光学谐振器是一种微纳米光学结构,基于有限模体积内的光-物质相互作用增强,能够将金刚石色心的发射与谐振器的增强效应相结合,有选择性地增强色心的发射,用于在光子电路中提供稳定且强度充足的光学信号。近年来,金刚石微纳加工技术的发展推动了金刚石光学谐振器的研究和应用。本文总结了金刚石光学谐振器的研究现状,概述了金刚石的基本性质、合成与加工方法,介绍了金刚石色心的生成以及其与光学谐振器的耦合原理,梳理了三种不同类型的金刚石光学谐振器的研究进展,并对未来金刚石光学谐振器的发展进行了展望。

快速响应的NV色心微波传感器实现及测量

高精度微波快速测量技术是电磁频谱分析监测的核心,微波测量技术为微波传感器的高精度测量提供了可能。通过建立NV色心空间磁场能级响应频率精密调谐模型,结合NV色心光学宽场成像技术,实现了高精度、响应快可调的微波测量。首先,通过连续光探测磁共振(ODMR)技术,结合宽场成像技术,通过像素级磁场强度-微波频率转化关系,实现宽场成像的微波测量;进而将连续扫频技术转变为施加定频进行检测,通过同步监测频点不同的响应特性,验证了测试结果的有效性。以上结果为高精度固态量子频谱分析仪、高瞬时带宽频谱微波传感器提供了重要技术基础。

高温高压非金属元素掺杂金刚石的研究进展

金刚石因其优越的极限特性,使得其应用领域非常广泛。金刚石的功能特性往往由其内部所含杂质元素决定,包括非金属元素如硼(B)、氮(N)、硫(S)和磷(P)等。掺杂这些单元素以合成金刚石一直是国内外研究课题的热点。本文首先介绍了金刚石单晶在高温高压条件下的合成方法及其研究发展现状,随后分析了硼(B)、氮(N)、硫(S)、磷(P)等单元素掺杂对金刚石晶体生长和电学等性能的影响。同时对金刚石在半导体中的应用以及金刚石中的含氮色心进行了分析。最后展望了掺杂后金刚石的光学和电学性能研究前景,并指出进一步探索多元素共掺杂的理论和实验方法对提升掺杂金刚石的性能具有重要意义。

Experimental investigation of vector static magnetic field detection using an NV center with a single first-shell ^(13)C nuclear spin in diamond

We perform a proof-of-principle experiment that uses a single negatively charged nitrogen–vacancy（NV） color center with a nearest neighbor ^13C nuclear spin in diamond to detect the strength and direction（including both polar and azimuth angles） of a static vector magnetic field by optical detection magnetic resonance（ODMR） technique. With the known hyperfine coupling tensor between an NV center and a nearest neighbor ^13C nuclear spin, we show that the information of static vector magnetic field could be extracted by observing the pulsed continuous wave（CW） spectrum.