Mercury spectrum lamp is an important part of Mercury Atomic Frequency Standard (MAFS), which is used for light pumping and state detection. It may limit the stability and the signal-to-noise ratio performance in MAFS. In this work, we experimentally demonstrate mercury spectrum lamp can work under an optimum mode by controlling the cold end temperature of the lamp. It is found the maximum radiation intensity at 194[Formula: see text]nm and the minimal 254[Formula: see text]nm/194[Formula: see text]nm ratio can be achieved simultaneously at about 55∘C. The minimal 254[Formula: see text]nm/194[Formula: see text]nm is about 24, which is an order of magnitude lower than the case in common. Meanwhile, the effect of RF excitation power on 254[Formula: see text]nm/194[Formula: see text]nm ratio and the self-absorption phenomenon of 254[Formula: see text]nm are also investigated. The result demonstrates RF excitation power has a stronger influence on the light intensity of 194[Formula: see text]nm than on that of 254[Formula: see text]nm. These experimental results could shed light on later fluorescence detection experiment in MAFS and other lamp-based applications.
Mercury spectrum lamp is an important part of Mercury Atomic Frequency Standard (MAFS), which is used for light pumping and state detection. It may limit the stability and the signal-to-noise ratio performance in MAFS. In this work, we experimentally demonstrate mercury spectrum lamp can work under an optimum mode by controlling the cold end temperature of the lamp. It is found the maximum radiation intensity at 194[Formula: see text]nm and the minimal 254[Formula: see text]nm/194[Formula: see text]nm ratio can be achieved simultaneously at about 55∘C. The minimal 254[Formula: see text]nm/194[Formula: see text]nm is about 24, which is an order of magnitude lower than the case in common. Meanwhile, the effect of RF excitation power on 254[Formula: see text]nm/194[Formula: see text]nm ratio and the self-absorption phenomenon of 254[Formula: see text]nm are also investigated. The result demonstrates RF excitation power has a stronger influence on the light intensity of 194[Formula: see text]nm than on that of 254[Formula: see text]nm. These experimental results could shed light on later fluorescence detection experiment in MAFS and other lamp-based applications.
Rubidium electrodeless lamp is one of the core components of rubidium atomic frequency standard. It plays the role of optical pumping and quantum state preparation, and realizes the particle number inversion between two ground states of rubidium atoms. The RF excitation frequency affects the effective light spectral distribution of rubidium electrodeless lamp, and then determines the pumping efficiency and the limiting frequency stability of rubidium atomic frequency standard. In this paper, the influence of RF excitation frequency on the spectral characteristics of rubidium electrodeless lamp can be optimized based on power compensation. It is found that there is a sensitive dependence between the heating rate and the excitation frequency of the rubidium electrodeless lamp, and the excitation frequency range corresponding to the turning point of the maximum heating rate was given experimentally. When the input power and the bubble wall temperature remain unchanged and the rubidium electrodeless lamp is in the ring-mode state, the spectral characteristics have a depression at the optimum resonance frequency. Therefore, the excitation frequency of the rubidium electrodeless lamp should be properly pulled to 5~9 MHz from the optimum resonant point, which can optimize the spectral characteristics of the rubidium electrodeless lamp and can improve the frequency stability of the rubidium atomic clock.
Rubidium spectral lamp is one of the critical parts in a rubidium atomic frequency standard (RAFS). The light emitted from the spectral lamp contains two components, one is the useful component, which contributes to the atomic transition signal, and the other is the useless component, which acts only as the light noise. In order to improve the signal-to-noise ratio of the frequency locking loop of a RAFS, and therefore to obtain a highly stable RAFS, it's very important to enhance the useful light component and suppress the useless component. In the present work the light spectra of the three commonly used rubidium spectrum lamps with bulbs separately filled with buffer gases argon, krypton and xenon were obtained by means of a monochromator. The spectra were analyzed and the methods to enhance useful light intensity and reduce useless light intensity were discussed. Results showed that the useful light intensity strongly depends on the types of buffer gases and the bulb temperature. In the whole range of bulb temperature, the Xe lamp had the highest useful light intensity among the three lamps. The Kr lamp showed a higher useful light intensity than the Ar lamp at low bulb temperature, while at high bulb temperature the Ar lamp showed a higher useful light intensity than the Kr lamp. Analysis also indicates that the light noise of a rubidium spectrum lamp can be effectively minimized by adopting suitable light filtering technique.
Rb lamp is a very critical component of the Rb atomic clock’s Physics Package. The Rb lamp’s performance is very sensitive to temperature and its stability. In this paper we discuss the behaviors of Rb Lamp with temperature. The Rb lamp exciter power and temperature of Rb bulb are very important parameters in controlling the performance of the Rb Lamp. It is observed that at temperatures beyond 110° C, the lamp mode changes from the ring to red mode resulting in abnormal broadening of emission lines and self reversal. The results of our studies on spectral analysis of Rb lamp under various operating conditions are reported in the paper.
We propose a method to determine the optimal power of the microwave resonance transition that simultaneously improves the signal-to-noise ratio and reduces line width based on saturation broadening theory and experiment. Saturation broadening spectra of the ground state hyperfine transition of trapped 199 Hg + ions are measured and analyzed. The value of the optimal microwave power is obtained by using the proposed method and is verified. Rabi oscillations decay spectra of trapped 199 Hg + ions are observed and the optimal microwave irradiation time for the maximum transition signal intensity is determined. This work will help to improve the short-term frequency stability of the mercury ion microwave frequency standard.
Abstract As I have shown in numerous publications, the vapour of mercury in vacuo, even at temperatures below the solidifying point of the metal, when illuminated by the light of a water-cooled quartz mercury lamp, emits the monochromatic radiation of wave-length 2536. According to Bohr’s theory, this resonance radiation results from the fall of an electron from the 2p2 orbit, to which it has been raised from the IS orbit by the absorption of one quantum of 2536 radiation, back to the IS orbit, the orbit occupied by the electron when the atom is in its normal state. An atom in which the electron has been brought to the 2p2 orbit is in a condition to absorb the radiation of any other line produced by the fall of electrons from outer orbits to orbit 2p2, and Fuchtbauer has shown, in an extremely interesting and important paper (‘Physik. Zeit.,’ 1920), that a large number of the arc lines of mercury are radiated by cold mercury vapour illuminated by the mercury arc. He showed that, if the 2536 radiation was screened off by glass, none of the other lines appeared, and explained their presence as the result of the absorption by excited atoms with electrons at the 2p2 level, of the radiations terminating at this level, by which the electrons are carried out to other-orbits, from which they can fall back in various ways, giving rise to emission lines in the process. Though Fuchtbauer‘s experiment did not prove that this process actually took place, his explanation was the only one possible on modern theory, and the experiments which are to be considered in the present paper show that it was correct. Twenty years ago the most that could have been said would have been that the absorption of the 2536 radiation “shook” the atom in some way, causing it to emit its other frequencies as a sort of fluorescence, since Fuchtbauer’s experiment did not show that excitation by lines other than the 2536 line was necessary for the emission of the arc spectrum. To demonstrate experimentally that the step-by-step transfer of electrons from orbit to orbit actually takes place, it is necessary to illuminate the mercury vapour with various combinations of monochromatic light, and study the resultant emission spectrum.
Abstract It is known that the fluorescence of mercury vapour can be excited by absorption in the region λ 1850, situated near the resonance line 1 1S0- 1 1P1, and in the region of band absorption λ 2345. It can also be excited by absorption in the region of the resonance line 1 1S0— 2 3P1 2536.52. In this latter case it has, I believe, been generally supposed that fluorescence is not obtained unless excitation is fairly close to the resonance line. Thus Prings-heim and Terenin found that a hot mercury lamp (punktlampe of Heraeus) or an overloaded ordinary 220-volt mercury lamp does not give band fluorescence of any kind. In the hot lamp the core of the resonance line is removed by self reversal. It is, however, well known that unexcited mercury vapour has an absorption band beginning near the resonance line 2537, and extending, if the vapour is dense, to a distance of some hundreds of Ångstroms towards longer waves. The question arises whether this absorption is accompanied by fluorescent emission or not.