Physical Review Letters

Excited-State Electronic Spectrum of Ruby

T. M. Dunn, A. H. Francis

Published Sep 14, 1970• 7 citations

Abstract

Two new sharp absorption systems have been observed in the excited-state electronic spectrum of ruby. Both systems originate from the lowest spin doublet state of chromium ion $^{2}E$ and are found at 15 006 and 27 465 ${\mathrm{cm}}^{\ensuremath{-}1}$ above the originating level. Both of the sharp systems are completely polarized perpendicular to the principal optic axis.

DOI: 10.1103/physrevlett.25.705

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Physical Review Letters

Excited-State Electronic Spectrum of Ruby

T. M. Dunn, A. H. Francis

Published Sep 14, 1970• 7 citations

Publisher

Abstract

Two new sharp absorption systems have been observed in the excited-state electronic spectrum of ruby. Both systems originate from the lowest spin doublet state of chromium ion

^{2}E

and are found at 15 006 and 27 465

{\mathrm{cm}}^{\ensuremath{-}1}

above the originating level. Both of the sharp systems are completely polarized perpendicular to the principal optic axis.

DOI: 10.1103/physrevlett.25.705

Related papers

Absorption Spectrum of Optically Pumped Ruby I. Experimental Studies of Spectrum in Excited States

Takashi Kushida

Absorption transitions between two excited optical states in ruby have been studied by comparing the absorption coefficients measured under optically pumped and unpumped conditions. The spectrum has been determined in the π-and σ-polarizations in the photon energy range from 5,500 to 45,000 cm -1 . Several absorption bands have been found which arise from the transitions from the excited states t 2g 3 2 E g and t 2g 3 2 T 1g of the Cr 3+ ion. From the locations and intensities of these bands, the terminal states of the observed transitions are assigned to the charge transfer state, the t 2g 3 2 T 2g state, and the doublet states belonging to the electron configuration t 2g 3 e g . Calculated energies between these states and the metastable states, t 2g 3 2 E g and t 2g 3 2 T 1g , are in good agreement with the peak energies of the observed absorption bands. The present experiment gives new information inaccessible by the ordinary ground state absorption measurement, such as the locations of several doublet states with the configuration t 2g 2 e g and the intensities of doublet-doublet transitions in ruby.Absorption transitions between two excited optical states in ruby have been studied by comparing the absorption coefficients measured under optically pumped and unpumped conditions. The spectrum has been determined in the π-and σ-polarizations in the photon energy range from 5,500 to 45,000 cm -1 . Several absorption bands have been found which arise from the transitions from the excited states t 2g 3 2 E g and t 2g 3 2 T 1g of the Cr 3+ ion. From the locations and intensities of these bands, the terminal states of the observed transitions are assigned to the charge transfer state, the t 2g 3 2 T 2g state, and the doublet states belonging to the electron configuration t 2g 3 e g . Calculated energies between these states and the metastable states, t 2g 3 2 E g and t 2g 3 2 T 1g , are in good agreement with the peak energies of the observed absorption bands. The present experiment gives new information inaccessible by the ordinary ground state absorption measurement, such as the locations of several doublet states with the configuration t 2g 2 e g and the intensities of doublet-doublet transitions in ruby.

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Physical ReviewMay 17, 196557 citations

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T. Kushida

Several experiments on optically excited ruby are described. First, absorption transitions initiated from the metastable states,t\min{2}\max{3}2Eandt\min{2}\max{3}2T1, are investigated in the photon energy range from 5500 to 45 000 cm-1. The absorption spectrum of these excited states is determined in both\pi-and σ-polarizations and assignments for the observed absorption bands are achieved. Obtained results are compared with other experiments reported in the literature. Next, emission properties of pink ruby are studied in the region near theRlines. The emission spectrum is determined point by point by means of intense flash excitation. The observed weak bands are ascribed to theR'and phonon assistedRtransitions. Laser actions in these bands are discussed and experimental results on phonon terminated laser amplification are presented. An experiment using a giant pulse as an excitation source reveals that the transition time fromt\min{2}\max{3}2Etot\min{2}\max{3}2T1is shorter than a fraction of 1μs at room temperature.Several experiments on optically excited ruby are described. First, absorption transitions initiated from the metastable states,t\min{2}\max{3}2Eandt\min{2}\max{3}2T1, are investigated in the photon energy range from 5500 to 45 000 cm-1. The absorption spectrum of these excited states is determined in both\pi-and σ-polarizations and assignments for the observed absorption bands are achieved. Obtained results are compared with other experiments reported in the literature. Next, emission properties of pink ruby are studied in the region near theRlines. The emission spectrum is determined point by point by means of intense flash excitation. The observed weak bands are ascribed to theR'and phonon assistedRtransitions. Laser actions in these bands are discussed and experimental results on phonon terminated laser amplification are presented. An experiment using a giant pulse as an excitation source reveals that the transition time fromt\min{2}\max{3}2Etot\min{2}\max{3}2T1is shorter than a fraction of 1μs at room temperature.

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Huang Jin, Henry W. Moos

The absorption cross sections of the ${\mathrm{Cr}}^{3+}$ ion in the metastable states $^{2}E (\overline{E} \mathrm{and} 2\overline{A})$ of lightly doped ruby (\ensuremath{\sim}0.01%) have been measured as a function of polarization at temperatures of 30, 105, and 296\ifmmode^\circ\else\textdegree\fi{}K in the region from 2300 to 7000 \AA{}. The lifetime of these states was measured by observing the decay rate of the excited-state absorption, and agreed with the value of the measured fluorescence decay rate at various temperatures. The population of the excited states was measured by the change of the area under the first two vibronic sidebands at low temperatures. At room temperature the population was measured by the change of transmitted intensity of a ruby laser.The absorption cross sections of the ${\mathrm{Cr}}^{3+}$ ion in the metastable states $^{2}E (\overline{E} \mathrm{and} 2\overline{A})$ of lightly doped ruby (\ensuremath{\sim}0.01%) have been measured as a function of polarization at temperatures of 30, 105, and 296\ifmmode^\circ\else\textdegree\fi{}K in the region from 2300 to 7000 \AA{}. The lifetime of these states was measured by observing the decay rate of the excited-state absorption, and agreed with the value of the measured fluorescence decay rate at various temperatures. The population of the excited states was measured by the change of the area under the first two vibronic sidebands at low temperatures. At room temperature the population was measured by the change of transmitted intensity of a ruby laser.

Physical ReviewSep 10, 196822 citations

Two new sharp absorption systems have been observed in the excited-state electronic spectrum of ruby. Both systems originate from the lowest spin doublet state of chromium ion

^{2}E

and are found at 15 006 and 27 465

{\mathrm{cm}}^{\ensuremath{-}1}

above the originating level. Both of the sharp systems are completely polarized perpendicular to the principal optic axis.

The magnetization of ruby in a magnetic field at 300\ifmmode^\circ\else\textdegree\fi{}K is changed when the ruby is optically pumped with linearly polarized radiation from a

Q

-switched ruby laser. With a magnetic field parallel to the trigonal axis, laser light polarized parallel to this axis induces transitions from the spin \ifmmode\pm\else\textpm\fi{}\textonehalf{} levels of the

^{4}A_{2}

ground state to the levels of the

\overline{E}(^{2}E)

excited state. The change in

{M}_{z}

is linearly proportional to

H

except near the anticrossing points of the

^{4}A_{2}

spin levels at 2.07 and 4.14 kG. At these field strengths, there is an enhancement of the magnetization caused by state mixing of the

^{4}A_{2}

wave functions. When

H

has a small component perpendicular to the

z

axis, a magnetization is detected parallel to this component in the vicinity of 4.14 kG. The effect requires a long ground-state relaxation time. In a separate experiment, the relaxation of

{M}_{z}

was found to vary from 0.13 \ensuremath{\mu}sec in zero magnetic field to a constant value of 0.57 \ensuremath{\mu}sec for fields above 60 G.

The absorption cross sections of the

{\mathrm{Cr}}^{3+}

ion in the metastable states

^{2}E (\overline{E} \mathrm{and} 2\overline{A})

of lightly doped ruby (\ensuremath{\sim}0.01%) have been measured as a function of polarization at temperatures of 30, 105, and 296\ifmmode^\circ\else\textdegree\fi{}K in the region from 2300 to 7000 \AA{}. The lifetime of these states was measured by observing the decay rate of the excited-state absorption, and agreed with the value of the measured fluorescence decay rate at various temperatures. The population of the excited states was measured by the change of the area under the first two vibronic sidebands at low temperatures. At room temperature the population was measured by the change of transmitted intensity of a ruby laser.