We present an experimental study of laser-induced continuum structure in cesium, performed by observing the birefringence and dichroism induced in the atomic medium by a circularly polarized laser embedding the 8s $^{2}$ ${\mathit{S}}_{1/2}$ state into the ionization continuum. The optimization of the sensitivity for the detection of the polarization rotation has allowed a high-accuracy measurement of the resonance profile. A quantitative comparison with theoretical predictions, taking into account the hyperfine structure of atomic levels, shows a clear evidence of a line-broadening effect due to cesium resonant collisions.We present an experimental study of laser-induced continuum structure in cesium, performed by observing the birefringence and dichroism induced in the atomic medium by a circularly polarized laser embedding the 8s $^{2}$${\mathit{S}}_{1/2}$ state into the ionization continuum. The optimization of the sensitivity for the detection of the polarization rotation has allowed a high-accuracy measurement of the resonance profile. A quantitative comparison with theoretical predictions, taking into account the hyperfine structure of atomic levels, shows a clear evidence of a line-broadening effect due to cesium resonant collisions.

Physical Review AMay 1, 199328 citations

Photoionization of Excited Cesium Atoms

K. J. Nygaard, R. E. Hebner

Physics of Electronic and Atomic Collisions: ICPEAC VIIJan 1, 19711 citation

Near-infrared multiphoton ionization of cesium

William R. Christian, R. N. Compton, John A. D. Stockdale +4 more

Experimental and theoretical results are presented for resonantly enhanced three-photon ionization of cesium atoms in the wavelength range from 830 to 950 nm. The accidental near resonance of the $6p^{2}P_{\frac{3}{2},\frac{1}{2}}$ levels at the one-photon energy and the near resonance at the two-photon level with the $6d^{2}D_{\frac{3}{2},\frac{5}{2}}$ states gives rise to large ionization signals and interesting anomalies in the relative intensities of the fine-structure levels. "Hybrid resonances" are observed which involve the production of $6p ^{2}P_{\frac{1}{2}}$ atoms from molecular cesium. One hybrid resonance involves ionization of the $6p ^{2}P_{\frac{1}{2}}$ state via an electric quadrupole transition ($6p ^{2}P_{\frac{1}{2}}\ensuremath{-}7p ^{2}P_{\frac{3}{2}}$). Both experimental and theoretical photoelectron angular distributions are compared for all of the observed resonances except for the $6p ^{2}P_{\frac{3}{2}}$ state where the signals were too weak for such a measurement. Agreement between experiment and theory is fair for three-photon ionization via the $6p^{2}P_{\frac{1}{2}}$ state. Comparison of experiment and theory for the case of the $6d^{2}D_{\frac{3}{2},\frac{5}{2}}$ states indicates that hyperfine coupling during the laser-pulse duration may be important. The angular distributions for the hybrid resonances show the general behavior predicted by theory but the features appear broadened.Experimental and theoretical results are presented for resonantly enhanced three-photon ionization of cesium atoms in the wavelength range from 830 to 950 nm. The accidental near resonance of the $6p^{2}P_{\frac{3}{2},\frac{1}{2}}$ levels at the one-photon energy and the near resonance at the two-photon level with the $6d^{2}D_{\frac{3}{2},\frac{5}{2}}$ states gives rise to large ionization signals and interesting anomalies in the relative intensities of the fine-structure levels. "Hybrid resonances" are observed which involve the production of $6p ^{2}P_{\frac{1}{2}}$ atoms from molecular cesium. One hybrid resonance involves ionization of the $6p ^{2}P_{\frac{1}{2}}$ state via an electric quadrupole transition ($6p ^{2}P_{\frac{1}{2}}\ensuremath{-}7p ^{2}P_{\frac{3}{2}}$). Both experimental and theoretical photoelectron angular distributions are compared for all of the observed resonances except for the $6p ^{2}P_{\frac{3}{2}}$ state where the signals were too weak for such a measurement. Agreement between experiment and theory is fair for three-photon ionization via the $6p^{2}P_{\frac{1}{2}}$ state. Comparison of experiment and theory for the case of the $6d^{2}D_{\frac{3}{2},\frac{5}{2}}$ states indicates that hyperfine coupling during the laser-pulse duration may be important. The angular distributions for the hybrid resonances show the general behavior predicted by theory but the features appear broadened.

Physical Review AOct 1, 198411 citations

Laser ionization and time-resolved ion collection in cesium vapor

E. Arimondo, F. Giammanco, Antonio Sasso +1 more

Optics CommunicationsOct 1, 198514 citations

Monitoring Dark-State Dynamics of a Single Nitrogen-Vacancy Center in Nanodiamond by Auto-Correlation Spectroscopy: Photonionization and Recharging

Mengdi Zhang, Bai‐Yan Li, Jing Liu

In this letter, the photon-induced charge conversion dynamics of a single Nitrogen-Vacancy (NV) center in nanodiamond between two charge states, negative (NV−) and neutral (NV0), is studied by the auto-correlation function. It is observed that the ionization of NV− converts to NV0, which is regarded as the dark state of the NV−, leading to fluorescence intermittency in single NV centers. A new method, based on the auto-correlation calculation of the time-course fluorescence intensity from NV centers, was developed to quantify the transition kinetics and yielded the calculation of transition rates from NV− to NV0 (ionization) and from NV0 to NV− (recharging). Based on our experimental investigation, we found that the NV−-NV0 transition is wavelength-dependent, and more frequent transitions were observed when short-wavelength illumination was used. From the analysis of the auto-correlation curve, it is found that the transition time of NV− to NV0 (ionization) is around 0.1 μs, but the transition time of NV0 to NV− (recharging) is around 20 ms. Power-dependent measurements reveal that the ionization rate increases linearly with the laser power, while the recharging rate has a quadratic increase with the laser power. This difference suggests that the ionization in the NV center is a one-photon process, while the recharging of NV0 to NV− is a two-photon process. This work, which offers theoretical and experimental explanations of the emission property of a single NV center, is expected to help the utilization of the NV center for quantum information science, quantum communication, and quantum bioimaging.In this letter, the photon-induced charge conversion dynamics of a single Nitrogen-Vacancy (NV) center in nanodiamond between two charge states, negative (NV−) and neutral (NV0), is studied by the auto-correlation function. It is observed that the ionization of NV− converts to NV0, which is regarded as the dark state of the NV−, leading to fluorescence intermittency in single NV centers. A new method, based on the auto-correlation calculation of the time-course fluorescence intensity from NV centers, was developed to quantify the transition kinetics and yielded the calculation of transition rates from NV− to NV0 (ionization) and from NV0 to NV− (recharging). Based on our experimental investigation, we found that the NV−-NV0 transition is wavelength-dependent, and more frequent transitions were observed when short-wavelength illumination was used. From the analysis of the auto-correlation curve, it is found that the transition time of NV− to NV0 (ionization) is around 0.1 μs, but the transition time of NV0 to NV− (recharging) is around 20 ms. Power-dependent measurements reveal that the ionization rate increases linearly with the laser power, while the recharging rate has a quadratic increase with the laser power. This difference suggests that the ionization in the NV center is a one-photon process, while the recharging of NV0 to NV− is a two-photon process. This work, which offers theoretical and experimental explanations of the emission property of a single NV center, is expected to help the utilization of the NV center for quantum information science, quantum communication, and quantum bioimaging.

NanomaterialsApr 10, 20213 citations

^{2}

{\mathit{S}}_{1/2}

state into the ionization continuum. The optimization of the sensitivity for the detection of the polarization rotation has allowed a high-accuracy measurement of the resonance profile. A quantitative comparison with theoretical predictions, taking into account the hyperfine structure of atomic levels, shows a clear evidence of a line-broadening effect due to cesium resonant collisions.

Experimental and theoretical results are presented for resonantly enhanced three-photon ionization of cesium atoms in the wavelength range from 830 to 950 nm. The accidental near resonance of the

6p^{2}P_{\frac{3}{2},\frac{1}{2}}

levels at the one-photon energy and the near resonance at the two-photon level with the

6d^{2}D_{\frac{3}{2},\frac{5}{2}}

states gives rise to large ionization signals and interesting anomalies in the relative intensities of the fine-structure levels. "Hybrid resonances" are observed which involve the production of

6p ^{2}P_{\frac{1}{2}}

atoms from molecular cesium. One hybrid resonance involves ionization of the

6p ^{2}P_{\frac{1}{2}}

state via an electric quadrupole transition ($6p ^{2}P_{\frac{1}{2}}\ensuremath{-}7p ^{2}P_{\frac{3}{2}}$). Both experimental and theoretical photoelectron angular distributions are compared for all of the observed resonances except for the

6p ^{2}P_{\frac{3}{2}}

state where the signals were too weak for such a measurement. Agreement between experiment and theory is fair for three-photon ionization via the

6p^{2}P_{\frac{1}{2}}

state. Comparison of experiment and theory for the case of the

6d^{2}D_{\frac{3}{2},\frac{5}{2}}

states indicates that hyperfine coupling during the laser-pulse duration may be important. The angular distributions for the hybrid resonances show the general behavior predicted by theory but the features appear broadened.