This article presents the results of experiments in which the 19 429.67-${\mathrm{cm}}^{\mathrm{\ensuremath{-}}1}$ emission of an ${\mathrm{Ar}}^{+}$ laser is used to pump the ${Z}_{1}$ , $^{4}\mathrm{I}_{9/2}$ , \ensuremath{\mu}=(5/2\ensuremath{\rightarrow} ${F}_{1}$ , $^{2}\mathrm{G}_{9/2}$ , \ensuremath{\mu}=(1/2 transition of ${\mathrm{Nd}}^{3+}$ ions dilutely substituted at ${\mathrm{La}}^{3+}$ sites in ${\mathrm{LaCl}}_{3}$ crystals in an \ensuremath{\sim}1.6-K bath of liquid He. In some of the work ${\mathrm{Er}}^{3+}$ ions are also present. When an external magnetic field is applied electron paramagnetic resonance (EPR) absorption of microwave energy by either ${\mathrm{Nd}}^{3+}$ or ${\mathrm{Er}}^{3+}$ results in marked intensity changes of ${\mathrm{Nd}}^{3+}$ fluorescence emissions. The essential new feature of this work is the observation of the importance of the effects of the heating of the crystal above the bath temperature by both optical and microwave absorption. The heating by phonons generated in the radiationless transitions associated with the optical pumping cycle results in the emission of 17 E and D ${\mathrm{Nd}}^{3+}$ fluorescences not observed in previous work with the crystal at \ensuremath{\sim}1.6 K. Because of the encapsulation of the crystals in silica envelopes in these experiments, the heating effects are especially marked at higher laser powers.These new fluorescences result from the state population redistributions effected by the rise in temperature of the crystal. EPR microwave absorption by either ${\mathrm{Nd}}^{3+}$ or ${\mathrm{Er}}^{3+}$ accompanied by spin-lattice relaxation results in a further increase in crystal temperature and further ${\mathrm{Nd}}^{3+}$ state population redistributions with concommitant changes in the intensities of the fluorescence emissions from these states of ${\mathrm{Nd}}^{3+}$ . This affords a new mechanism for optically detected magnetic resonance (ODMR) of these rare-earth ions. This new mechanism for ODMR produces optical signals strikingly different from those previously studied which result from the changes in the populations of the two components of the ground ${Z}_{1}$ doublet of ${\mathrm{Nd}}^{3+}$ produced by ${Z}_{1}$ microwave absorption or by microwave absorption by the ${\mathrm{Er}}^{3+}$ ground doublet with subsequent transfer of Zeeman quanta between ${\mathrm{Er}}^{3+}$ and ${\mathrm{Nd}}^{3+}$ and resultant changes in optical pumping rates and fluorescence emissions. The factors contributing to the new mechanism for ODMR also account for the observed changes with temperature in the characters of the decays of the ODMR signals when microwave irradiation is terminated. With constant intensity laser irradiation in the absence of external magnetic fields the 28 observed fluorescence emissions oscillate in synchrony at frequencies (1/2 to (1/3 Hz, when the laser irradiation intensity lies in a certain narrow range. Several mechanisms considered as explanations of this phenomenon have failed to account for its observed features. It is clear, however, that these oscillations of emission intensity are accompanied by oscillations in the temperature of the crystal and of the populations of the emitting states.This article presents the results of experiments in which the 19 429.67-${\mathrm{cm}}^{\mathrm{\ensuremath{-}}1}$ emission of an ${\mathrm{Ar}}^{+}$ laser is used to pump the ${Z}_{1}$, $^{4}\mathrm{I}_{9/2}$, \ensuremath{\mu}=(5/2\ensuremath{\rightarrow}${F}_{1}$, $^{2}\mathrm{G}_{9/2}$, \ensuremath{\mu}=(1/2 transition of ${\mathrm{Nd}}^{3+}$ ions dilutely substituted at ${\mathrm{La}}^{3+}$ sites in ${\mathrm{LaCl}}_{3}$ crystals in an \ensuremath{\sim}1.6-K bath of liquid He. In some of the work ${\mathrm{Er}}^{3+}$ ions are also present. When an external magnetic field is applied electron paramagnetic resonance (EPR) absorption of microwave energy by either ${\mathrm{Nd}}^{3+}$ or ${\mathrm{Er}}^{3+}$ results in marked intensity changes of ${\mathrm{Nd}}^{3+}$ fluorescence emissions. The essential new feature of this work is the observation of the importance of the effects of the heating of the crystal above the bath temperature by both optical and microwave absorption. The heating by phonons generated in the radiationless transitions associated with the optical pumping cycle results in the emission of 17 E and D ${\mathrm{Nd}}^{3+}$ fluorescences not observed in previous work with the crystal at \ensuremath{\sim}1.6 K. Because of the encapsulation of the crystals in silica envelopes in these experiments, the heating effects are especially marked at higher laser powers.These new fluorescences result from the state population redistributions effected by the rise in temperature of the crystal. EPR microwave absorption by either ${\mathrm{Nd}}^{3+}$ or ${\mathrm{Er}}^{3+}$ accompanied by spin-lattice relaxation results in a further increase in crystal temperature and further ${\mathrm{Nd}}^{3+}$ state population redistributions with concommitant changes in the intensities of the fluorescence emissions from these states of ${\mathrm{Nd}}^{3+}$. This affords a new mechanism for optically detected magnetic resonance (ODMR) of these rare-earth ions. This new mechanism for ODMR produces optical signals strikingly different from those previously studied which result from the changes in the populations of the two components of the ground ${Z}_{1}$ doublet of ${\mathrm{Nd}}^{3+}$ produced by ${Z}_{1}$ microwave absorption or by microwave absorption by the ${\mathrm{Er}}^{3+}$ ground doublet with subsequent transfer of Zeeman quanta between ${\mathrm{Er}}^{3+}$ and ${\mathrm{Nd}}^{3+}$ and resultant changes in optical pumping rates and fluorescence emissions. The factors contributing to the new mechanism for ODMR also account for the observed changes with temperature in the characters of the decays of the ODMR signals when microwave irradiation is terminated. With constant intensity laser irradiation in the absence of external magnetic fields the 28 observed fluorescence emissions oscillate in synchrony at frequencies (1/2 to (1/3 Hz, when the laser irradiation intensity lies in a certain narrow range. Several mechanisms considered as explanations of this phenomenon have failed to account for its observed features. It is clear, however, that these oscillations of emission intensity are accompanied by oscillations in the temperature of the crystal and of the populations of the emitting states.

Physical review. B, Condensed matterMar 1, 19894 citations

Fluorescent excitation of mercury by the resonance frequency and by lower frequencies.—V

Robert John Strutt

Abstract It was shown at an early stage of the present workf that the characteristic fluorescence of mercury could be generated by wave-lengths much longer than the resonance line λ 2537; indeed, its excitation was traced as far as λ 3450. It was found also that the primary excitation by atomic absorption (core of the resonance line) could be distinguished from excitation by molecular absorption (wing of the resonance line). Although in the case of the longer waves it appears certain that the excited systems produced in the first instance by absorption are molecules and not atoms, yet it is possible that subsequent dissociation, or excitation by collision might lead to the formation of excited atoms in a secondary way.Abstract It was shown at an early stage of the present workf that the characteristic fluorescence of mercury could be generated by wave-lengths much longer than the resonance line λ 2537; indeed, its excitation was traced as far as λ 3450. It was found also that the primary excitation by atomic absorption (core of the resonance line) could be distinguished from excitation by molecular absorption (wing of the resonance line). Although in the case of the longer waves it appears certain that the excited systems produced in the first instance by absorption are molecules and not atoms, yet it is possible that subsequent dissociation, or excitation by collision might lead to the formation of excited atoms in a secondary way.

Proceedings of the Royal Society of London Series A Containing Papers of a Mathematical and Physical CharacterMar 3, 19330 citations

Principles of Absorption and Fluorescence

Stephen H. Ashworth

Springer eBooksJan 1, 20020 citations

Light quenching effects at high-saturation conditions

M. Jadan

Computer modelling of fluorescence light quenching is performed with no limitations on the optical wave intensities.The main attention is paid to searching for such combinations of polarizations of the interacting waves that provide minimal polarization changes for the waves passing through a cell.From the viewpoint mentioned above, the most appropriate case is circular polarization of the pumping wave.The efficiency parameter of amplification of the quenching wave can be used for checking mutual orientations of the dipoles responsible for absorption and emission.We show that the light quenching can produce appreciable changes in the polarization of fluorescence light passing through the cell.Computer modelling of fluorescence light quenching is performed with no limitations on the optical wave intensities.The main attention is paid to searching for such combinations of polarizations of the interacting waves that provide minimal polarization changes for the waves passing through a cell.From the viewpoint mentioned above, the most appropriate case is circular polarization of the pumping wave.The efficiency parameter of amplification of the quenching wave can be used for checking mutual orientations of the dipoles responsible for absorption and emission.We show that the light quenching can produce appreciable changes in the polarization of fluorescence light passing through the cell.

Ukrainian Journal of Physical OpticsJan 1, 20141 citation

Comments on the Resonance Fluorescence in Gases

C. Alden Mead, Hendrik F. Hameka

The Journal of Chemical PhysicsJan 15, 19641 citation

This article presents the results of experiments in which the 19 429.67-${\mathrm{cm}}^{\mathrm{\ensuremath{-}}1}$ emission of an

{\mathrm{Ar}}^{+}

laser is used to pump the

{Z}_{1}

^{4}\mathrm{I}_{9/2}

, \ensuremath{\mu}=(5/2\ensuremath{\rightarrow}

{F}_{1}

^{2}\mathrm{G}_{9/2}

, \ensuremath{\mu}=(1/2 transition of

{\mathrm{Nd}}^{3+}

ions dilutely substituted at

{\mathrm{La}}^{3+}

sites in

{\mathrm{LaCl}}_{3}

crystals in an \ensuremath{\sim}1.6-K bath of liquid He. In some of the work

{\mathrm{Er}}^{3+}

ions are also present. When an external magnetic field is applied electron paramagnetic resonance (EPR) absorption of microwave energy by either

{\mathrm{Nd}}^{3+}

{\mathrm{Er}}^{3+}

results in marked intensity changes of

{\mathrm{Nd}}^{3+}

fluorescence emissions. The essential new feature of this work is the observation of the importance of the effects of the heating of the crystal above the bath temperature by both optical and microwave absorption. The heating by phonons generated in the radiationless transitions associated with the optical pumping cycle results in the emission of 17 E and D

{\mathrm{Nd}}^{3+}

fluorescences not observed in previous work with the crystal at \ensuremath{\sim}1.6 K. Because of the encapsulation of the crystals in silica envelopes in these experiments, the heating effects are especially marked at higher laser powers.These new fluorescences result from the state population redistributions effected by the rise in temperature of the crystal. EPR microwave absorption by either

{\mathrm{Nd}}^{3+}

{\mathrm{Er}}^{3+}

accompanied by spin-lattice relaxation results in a further increase in crystal temperature and further

{\mathrm{Nd}}^{3+}

state population redistributions with concommitant changes in the intensities of the fluorescence emissions from these states of

{\mathrm{Nd}}^{3+}

. This affords a new mechanism for optically detected magnetic resonance (ODMR) of these rare-earth ions. This new mechanism for ODMR produces optical signals strikingly different from those previously studied which result from the changes in the populations of the two components of the ground

{Z}_{1}

doublet of

{\mathrm{Nd}}^{3+}

produced by

{Z}_{1}

microwave absorption or by microwave absorption by the

{\mathrm{Er}}^{3+}

ground doublet with subsequent transfer of Zeeman quanta between

{\mathrm{Er}}^{3+}

and

{\mathrm{Nd}}^{3+}

and resultant changes in optical pumping rates and fluorescence emissions. The factors contributing to the new mechanism for ODMR also account for the observed changes with temperature in the characters of the decays of the ODMR signals when microwave irradiation is terminated. With constant intensity laser irradiation in the absence of external magnetic fields the 28 observed fluorescence emissions oscillate in synchrony at frequencies (1/2 to (1/3 Hz, when the laser irradiation intensity lies in a certain narrow range. Several mechanisms considered as explanations of this phenomenon have failed to account for its observed features. It is clear, however, that these oscillations of emission intensity are accompanied by oscillations in the temperature of the crystal and of the populations of the emitting states.