A new method for obtaining inverse population between quadrupole sublevels of the ground state 5/2 + (0.0) and the isomeric state 3/2 + (7.6 eV) of the 229 Th nucleus in a dielectric crystal with a large band gap by means of an external source of VUV radiation is proposed. The method is based on an efficient depopulation of the upper sublevels of the ground state of 229 Th by resonant photons from a narrowband laser or a broader tunable free electron laser. The sublevels of the isomeric state play the role of intermediate states. The proposed scheme of optical pumping (1) results in inverse population of nuclear sublevels without using extremely low temperatures, and (2) shows a new means of creating a gamma-ray laser of optical range at the nuclear transition in 229 Th (a) in crystals with isovalent substitution of host ions (e.g. Si 4+ ions in the SiO 2 crystal replaced by the 229 Th 4+ ions) and (b) in crystals such as Na 2 ThF 6 , where the substitution is not necessary.A new method for obtaining inverse population between quadrupole sublevels of the ground state 5/2 + (0.0) and the isomeric state 3/2 + (7.6 eV) of the 229 Th nucleus in a dielectric crystal with a large band gap by means of an external source of VUV radiation is proposed. The method is based on an efficient depopulation of the upper sublevels of the ground state of 229 Th by resonant photons from a narrowband laser or a broader tunable free electron laser. The sublevels of the isomeric state play the role of intermediate states. The proposed scheme of optical pumping (1) results in inverse population of nuclear sublevels without using extremely low temperatures, and (2) shows a new means of creating a gamma-ray laser of optical range at the nuclear transition in 229 Th (a) in crystals with isovalent substitution of host ions (e.g. Si 4+ ions in the SiO 2 crystal replaced by the 229 Th 4+ ions) and (b) in crystals such as Na 2 ThF 6 , where the substitution is not necessary.

Laser Physics LettersSep 2, 201329 citations

Lasers without population inversion

O. A. Kocharovskaia, Paul Mandel, Ia. I. Khanin

Известия Российской академии наук Физика атмосферы и океанаJan 1, 19905 citations

Creation of the inverse population in the $^{229}$ Th ground-state doubletCreation of the inverse population in the $^{229}$Th ground-state doublet

Evgenii V. Tkalya, Леонід Петрович Яценко

A new method for obtaining of inverse population between quadrupole sublevels of the ground state $5/2^+(0.0)$ and the isomeric state $3/2^+(7.6$ eV) of the $^{229}$ Th nucleus in a dielectric crystal with a large band gap by means of external source of the VUV radiation is proposed. The method is based on an efficient depopulation of the upper sublevels of the ground state of $^{229}$ Th by resonant photons from narrowband laser or broader tunable free electron laser. Sublevels of the isomeric state play the role of intermediate states. In addition, we have considered a case of excitation of the isomeric state (without creation of inverse population) by broadband source of light with the anti-Stokes scattering. The proposed scheme of optical pumping results in (1) inverse population of nuclear sublevels without using extremely low temperatures, and (2) shows a new way for the creation of the gamma-ray laser of optical range at the nuclear transition in $^{229}$ Th (a) in crystals with isovalent substitution of host ions (eg Si $^{4+}$ ions in the SiO $_2$ crystal replaced by the $^{229}$ Th $^{4+}$ ions) and (b) in crystals such as Na $_2$ ThF $_6$ , where the substitution is not necessary.A new method for obtaining of inverse population between quadrupole sublevels of the ground state $5/2^+(0.0)$ and the isomeric state $3/2^+(7.6$ eV) of the $^{229}$Th nucleus in a dielectric crystal with a large band gap by means of external source of the VUV radiation is proposed. The method is based on an efficient depopulation of the upper sublevels of the ground state of $^{229}$Th by resonant photons from narrowband laser or broader tunable free electron laser. Sublevels of the isomeric state play the role of intermediate states. In addition, we have considered a case of excitation of the isomeric state (without creation of inverse population) by broadband source of light with the anti-Stokes scattering. The proposed scheme of optical pumping results in (1) inverse population of nuclear sublevels without using extremely low temperatures, and (2) shows a new way for the creation of the gamma-ray laser of optical range at the nuclear transition in $^{229}$Th (a) in crystals with isovalent substitution of host ions (eg Si$^{4+}$ ions in the SiO$_2$ crystal replaced by the $^{229}$Th$^{4+}$ ions) and (b) in crystals such as Na$_2$ThF$_6$, where the substitution is not necessary.

arXiv:1308.1125Aug 5, 20130 citations

Field and population fluctuations in a laser

W. H. Louisell, M. Lax

IEEE Journal of Quantum ElectronicsMay 1, 19680 citations

Population Inversion and Consideration of Energy Levels of a Lasing Medium

Dhruba J. Biswas

Undergraduate lecture notes in physicsJan 1, 20230 citations

Engineering the initial state in broadband population inversion

Bo Y. Chang, Sheokmin Shin, Ignacio R. Solá

Quantum systems with sublevel structures prevent full population inversion from one manifold of sublevels to the other using strong ultrafast resonant pulses. In this work we explain the mechanism by which this population transfer is blocked. We then develop a novel concept of geometric control, assuming full or partial coherent manipulation within the manifolds and show that by preparing specific coherent superpositions in the initial manifold, full population inversion or full population blockade, {\it i.e} laser-induced transparency, can be achieved. In particular, by parallel population transfer we show how population inversion between the manifolds can be obtained with minimal pulse area. As the number of sublevels increases, population inversion can overcome the pulse area theorem at the expense of full control over the initial manifold of sublevels.Quantum systems with sublevel structures prevent full population inversion from one manifold of sublevels to the other using strong ultrafast resonant pulses. In this work we explain the mechanism by which this population transfer is blocked. We then develop a novel concept of geometric control, assuming full or partial coherent manipulation within the manifolds and show that by preparing specific coherent superpositions in the initial manifold, full population inversion or full population blockade, {\it i.e} laser-induced transparency, can be achieved. In particular, by parallel population transfer we show how population inversion between the manifolds can be obtained with minimal pulse area. As the number of sublevels increases, population inversion can overcome the pulse area theorem at the expense of full control over the initial manifold of sublevels.

arXiv:1503.00956Mar 3, 20150 citations

Creation of the inverse population in the

^{229}

Th ground-state doublet

A new method for obtaining of inverse population between quadrupole sublevels of the ground state

5/2^+(0.0)

and the isomeric state

3/2^+(7.6

eV) of the

^{229}

Th nucleus in a dielectric crystal with a large band gap by means of external source of the VUV radiation is proposed. The method is based on an efficient depopulation of the upper sublevels of the ground state of

^{229}

Th by resonant photons from narrowband laser or broader tunable free electron laser. Sublevels of the isomeric state play the role of intermediate states. In addition, we have considered a case of excitation of the isomeric state (without creation of inverse population) by broadband source of light with the anti-Stokes scattering. The proposed scheme of optical pumping results in (1) inverse population of nuclear sublevels without using extremely low temperatures, and (2) shows a new way for the creation of the gamma-ray laser of optical range at the nuclear transition in

^{229}

Th (a) in crystals with isovalent substitution of host ions (eg Si

^{4+}

ions in the SiO

_2

crystal replaced by the

^{229}

^{4+}

ions) and (b) in crystals such as Na

_2

ThF

_6

, where the substitution is not necessary.