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Extra dimensions and atomic transition frequencies

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Chinese Physics B 2008年第1期17卷 70-75页

作者：李志刚倪维斗 Antonio Pulido Patón Center for Gravitation and Cosmology Purple Mountain ObservatoryChinese Academy of Sciences

New unification theories predict large extra dimensions （LEDs）. If that is the case, gravity would be stronger at short ranges than what Newtonian gravity predicts. LEDs could also have effects at atomic level. In this paper we propose a new method to constrain the size of ‘gravity-only’ LEDs by analysing how these LEDs modify the energy of the atomic transitions 1s-2s and 2s-2p （Lamb shift）, in the particular case of the hydrogen and muonium atoms. We estimate these effects by using Bethe＇s non-relativistic treatment of Lamb shift. In the particular case of three LEDs, which may be a candidate to explain the interaction mechanism of dark matter particles, we have found that current knowledge in atomic spectroscopy could constrain their sizes to less than 10 μm. Although our contributions do not reach the sensitivity given by SN1987a, they are still slightly better than recent constraints given by Inverse Square Law tests of the Eoet-Wash group at Washington University, which gave R3 〈 36.6 μm.

关键词： large extra dimensions Lamb shift atomic spectroscopy

Analysis of the time-domain spectrum of hydrogen in electric field near helium surface

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Chinese Optics Letters 2011年第4期9卷 5-8页

作者：龚晓青杨光参 School of Physics and Electronic Information Engineering Wenzhou University

The Ryderberg electronic wave packet dynamics of hydrogen atom near helium surface in an electric field is investigated using the semiclassical method. The autocorrelation function is calculated when the photoionized electron is excited by a short laser pulse for different atom-surface separations. The results show that new recurrences appear because of the helium surface, and the number of recurrent peaks increases with the decrease in atom-surface distance. The new feature is ascribed to the bifurcation of new closed orbits in the classical dynamics of the photoionized electron. Therefore, surface properties have a significant effect on the spectrum of nearby atoms or ions.

关键词： atomic spectroscopy Atoms Electric fields Helium Hydrogen Photoionization Regression analysis Surface properties

Electroless nickel plating on optical fiber probe

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Chinese Optics Letters 2009年第6期7卷 472-474页

作者：黄立王周锋李卓民邓文礼 College of Materials Science and Engineering South China University of Technology

As a component of near-field scanning optical microscope （NSOM）, optical fiber probe is an important factor influncing the equipment resolution. Electroless nickel plating is introduced to metallize the optical fiber probe. The optical fibers are etched by 40% HF with Turner etching method. Through pretreatment, the optical fiber probe is coated with Ni-P film by electroless plating in a constant temperature water tank. atomic absorption spectrometry （AAS）, scanning electron microscopy （SEM）, and energy dispersive X-ray spectrometry （EDXS） are carried out to characterize the deposition on fiber probe. We have reproducibly fabricated two kinds of fiber probes with a Ni-P film： aperture probe and apertureless probe. In addition, reductive particle transportation on the surface of fiber probe is proposed to explain the cause of these probes.

关键词： Absorption spectroscopy atomic absorption spectrometry atomic spectroscopy Fiber optics Fibers Nickel Nickel alloys Nickel plating Optical fiber fabrication Optical fibers Optical materials Photoresists Scanning Scanning electron microscopy Spectrometers Water tanks

Second harmonic 423-nm laser generated by BIBO crystal for calcium optical frequency standard

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Chinese Optics Letters 2008年第5期6卷 317-319页

作者：陈振辉鹿博徐志学庄伟于闯于得水黄凯凯陈徐宗陈景标 School of Electronics Engineering and Computer Science Peking University Beijing Uni-Quanta Co.Ltd

Calcium is one prospective element for the modern optical frequency standard. The 423-nm transition line of calcium atoms has been widely used in laser slowing and laser cooling, the precise spectrum measurement, and the magnetic optical trapping （MOT）. However, there is no any available commercial diode laser working at this wavelength. We built a 423-nm laser based on extra bow-tie cavity and by using a Brewstercut uncoated BIBO （BiB306） crystal, which worked at room temperature, with conversion efficiency of 3.75%, and a potential up to 20%.

关键词： atomic spectroscopy Calcium Cooling Frequency standards Laser cooling Natural frequencies Optical materials

Kinetics analysis of chemiluminescence in discharge-driven HF chemical lasers

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Chinese Optics Letters 2011年第8期9卷 52-54页

作者：罗威袁圣付闫宝珠陆启生邹前进 College of Opto-electric Science and Engineer National University of Defense Technology

The chemiluminescence spectrum in the optical cavity of discharge-driven hydrogen fluoride （HF） chemical laser is measured. The result reveals that the spectra of the helium and fluorine （F） atoms are the major components. Moreover, the green chemiluminescence in the downstream of the optical axis is mostly composed of the 60P20 spectral line of the HF molecule. The analysis shows that, except for the cold pumping reaction, the recombination of the F atoms and the hot pumping reaction also occur in the optical cavity. Due to the hot pumping reaction and the opticM cavity temperature in a specific range, the 60P20 line becomes the strongest HF molecule in the downstream region of the optical axis. After the hot pumping reaction, the green chemiluminescence always appears in the downstream region of the optical axis when the optical cavity temperature varies in a ~reater ran~.

关键词： atomic spectroscopy Chemical analysis Chemical lasers Fluorine Helium Laser chemistry Pumps

Novel yellow colored flame compositions with superior spectral performance

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Defence Technology（防务技术） 2017年第1期13卷 33-39页

作者： Ramy Sadek Mohamed Kassem Mohamed Abdo Sherif Elbasuney School of Chemical Engineering Military Technical CollegeKobry El-KobbaCairoEgypt

The production of colored flames is the primary purpose of military signaling, projectile tracing, and illuminating devices. Certain elements and compounds when heated to high temperature have the unique property of emitting lines or narrow bands in the visible region(380-780 nm). This study, reports on the development of novel yellow colored flame compositions with enhanced spectral performance in terms of luminous intensity, and color quality to standard Russian yellow tracer. The light intensity and the imprint spectra of developed yellow flares were measured using digital luxmeter and UV e Vis. spectrometer respectively. The main giving of this study is that the light intensity, and color quality of Russian yellow tracer were improved by 287%, and 170% respectively. This was accomplished by means of optimizing the ratio of novel binder to color source using aluminum metal fuel. Aluminumbased formulations were found to maximize the formation of yellow reactive emitting specimens, and to eliminate any interfering incandescent emission resulted from Mg O. Quantification of yellow color emitting specimens in the combustion gaseous products was achieved using chemical equilibrium thermodynamic code named ICT(Institute of Chemical Technology in Germany, Virgin 2008); in an attempt to judge the light quality. This improvement in yellow flare performance established the rule that the emission intensity increases as the reaction temperature increases. In the meantime upper limit of temperature was avoided to maximize the color quality.

关键词： Pyrotechnics Colored flames Yellow tracer atomic spectroscopy Color quality

A multi-band atomic candle with microwave-dressed Rydberg atoms

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Frontiers of physics 2023年第1期18卷 201-207页

作者： Yafen Cai Shuai Shi Yijia Zhou Jianhao Yu Yali Tian Yitong Li Kuan Zhang Chenhao Du Weibin Li Lin Li MOE Key Laboratory of Fundamental Physical Quantities Measurement Hubei Key Laboratory of Gravitation and Quantum PhysicsPGMFInstitute for Quantum Science and EngineeringSchool of PhysicsHuazhong University of Science and TechnologyWuhan 430074China Graduate School of China Academy of Engineering Physics Beijing 100193China School of Physics and Astronomy and Centre for the Mathematics and Theoretical Physics of Quantum Non-equilibrium Systems University of NottinghamNottinghamNG72RDUK

Stabilizing important physical quantities to atom-based standards lies at the heart of modern atomic,molecular and optical physics,and is widely applied to the field of precision *** particular importance is the atom-based microwave field amplitude stabilizer,the so-called atomic *** atomic candles are realized with atoms in their ground state,and hence suffer from the lack of frequency band tunability and small stabilization bandwidth,severely limiting their development and potential *** tackle these limitations,we employ microwave-dressed Rydberg atoms to realize a novel atomic candle that features multi-band frequency tunability and large stabilization *** demonstrate amplitude stabilization of microwave field from C-band to Ka-band,which could be extended to quasi-DC and terahertz fields by exploring abundant Rydberg *** atomic candle achieves stabilization bandwidth of 100 Hz,outperforming previous ones by more than two orders of *** simulation indicates the stabilization bandwidth can be further increased up to 100 *** work paves a route to develop novel electric field control and applications with a noise-resilient,miniaturized,sensitive and broadband atomic candle.

关键词： Rydberg atoms microwave atomic spectroscopy

Improvement of hybridization signals of gold label silver stain gene detection

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Journal of Southeast University(English Edition) 2004年第4期20卷 463-466页

作者：聂立波陈洪谭美君何农跃东南大学分子与生物分子电子学教育部重点实验室南京210096 中南林学院生命科学技术系长沙410004 株洲工学院包装印刷学院株洲412008

The factors that influence the colorimetric gene detection of gold label silver stain and improve the detection signals were studied. The influence of amino DNA probes and thiol DNA modified gold nanoparticles was investigated based on a sandwich hybridization system. An increase in amino probe concentration brought about an increase in hybridization signal which reached a threshold corresponding to the saturated concentration of amino probes bounded onto a glass slide surface. Since the steric hindrance effect of nanoparticles was dominant over the influence of a surface area, the bigger gold nanoparticles led to weaker hybridization signals. The hybridization efficiency enhanced significantly with the increase of the thiol DNA modified nanoparticle concentrations. Experimental results showed that 125 μmol/L of the amino DNA probe concentration, 15 nm of the gold nanoparticle diameter, and 4.07 nmol/L of the thiol DNA modified gold nanoparticle concentration were optimal for the detection system. The hybridization signals can be improved remarkably by choosing optimal hybridization conditions.

关键词： atomic spectroscopy Colorimetric analysis DNA Gold Probes Silver Supramolecular chemistry