An optical characterization of the Stark components of the 1D2 and 3H4 manifolds has been performed using the fluorescence spectra for the 1D2→3H4 transition of Pr3+ in Sr5(PO4)3F laser host at 10 K. The temperature dependencies of the spectral width, position, and shift of the sharp, intense inter-Stark transition of the 623.6 (X2→Y5) nm line within the 1D2→3H4 inter-manifold transition have been also investigated. The linewidth of this transition was found to increase with increasing crystal temperature. Also, the 623.6 nm line was found to shift toward the longer wavelength (redshift) as temperature was increased. The experimental results of the temperature dependent width and shift of this line are explained in light of the Debye model, which invokes phonon-ion interaction in crystalline solids.An optical characterization of the Stark components of the 1D2 and 3H4 manifolds has been performed using the fluorescence spectra for the 1D2→3H4 transition of Pr3+ in Sr5(PO4)3F laser host at 10 K. The temperature dependencies of the spectral width, position, and shift of the sharp, intense inter-Stark transition of the 623.6 (X2→Y5) nm line within the 1D2→3H4 inter-manifold transition have been also investigated. The linewidth of this transition was found to increase with increasing crystal temperature. Also, the 623.6 nm line was found to shift toward the longer wavelength (redshift) as temperature was increased. The experimental results of the temperature dependent width and shift of this line are explained in light of the Debye model, which invokes phonon-ion interaction in crystalline solids.

Journal of Applied PhysicsOct 15, 20004 citations

Optical Spectral Linewidths in Solids

R. M. Macfarlane

Springer series in optical sciences/SPringer series in optical sciencesJan 1, 19875 citations

Spectral Properties of a Single-Mode Ruby Laser: Evidence of Homogeneous Broadening of the Zero-Phonon Lines in Solids

Carson L. Tang, H. Statz, G. A. deMars +1 more

According to several recent studies, the width of the sharp zero-phonon lines in the electronic spectra of impurities in solids, such as the $R$ lines of ruby, is due to Raman scattering of phonons by the impurity ions. The question whether such zero-phonon lines are homogeneously broadened is an important one, both for its own interest and for optical-maser applications. From a detailed study of the stimulated-emission spectra of a ruby laser operating in the traveling-wave modes, we obtain conclusive evidence that such zero-phonon lines are homogeneously broadened. Because the ${R}_{1}$ line of ruby is essentially homogeneously broadened at room temperature, the traveling-wave laser oscillates for all practical purposes only in a single mode. The spectral width of the laser emission is extremely sharp. It is less than 0.005 ${\mathrm{cm}}^{\ensuremath{-}1}$ at room temperature as compared to a width of the order of 1 ${\mathrm{cm}}^{\ensuremath{-}1}$ for conventional ruby lasers of comparable intensity. In addition, the output intensity no longer shows random spikes but shows a predictable train of regularly spaced spikes which agree well with theory.According to several recent studies, the width of the sharp zero-phonon lines in the electronic spectra of impurities in solids, such as the $R$ lines of ruby, is due to Raman scattering of phonons by the impurity ions. The question whether such zero-phonon lines are homogeneously broadened is an important one, both for its own interest and for optical-maser applications. From a detailed study of the stimulated-emission spectra of a ruby laser operating in the traveling-wave modes, we obtain conclusive evidence that such zero-phonon lines are homogeneously broadened. Because the ${R}_{1}$ line of ruby is essentially homogeneously broadened at room temperature, the traveling-wave laser oscillates for all practical purposes only in a single mode. The spectral width of the laser emission is extremely sharp. It is less than 0.005 ${\mathrm{cm}}^{\ensuremath{-}1}$ at room temperature as compared to a width of the order of 1 ${\mathrm{cm}}^{\ensuremath{-}1}$ for conventional ruby lasers of comparable intensity. In addition, the output intensity no longer shows random spikes but shows a predictable train of regularly spaced spikes which agree well with theory.

Physical ReviewOct 5, 196453 citations

Line “narrowing” in strong optical fields

Taras Plakhotnik

Journal of LuminescenceFeb 5, 20042 citations

Observation of sub-kilohertz resonance in Rf-Optical double resonance experiment in rare earth ions in solids

M. K. Kim, Byoung Seung HAM, Philip Hemmer +1 more

We have observed kilohertz and sub-kilohertz resonance structures in RF-optical double resonance experiments of rare-earth-doped solids, when the frequency of the RF ® eld is scanned across the hyper® ne transitions while monitoring the resonant optical absorption of a CW laser. The ea ect is observed only when the laser spectral width is broad compared to the hyper® ne structure. The observed line widths are apparently free of the inhomogeneous widths of hyper® ne levels and the line shape has peculiar double peak structure. The ea ect is modelled with a resonance involving three atomic levels interacting with three electromagnetic ® elds, two optical and one RF, in a triangular ordelta' con® guration. While the ordinary optical- RF two-® eld resonance is limited by spin inhomogeneous width, the simul- taneous excitation of three coupled transitions leads to narrow and highly nonlinear resonance structures that are not averaged by the inhomogeneous distribution of hyper® ne transition. We have observed a peculiarly narrow resonance structure in the course of optical-RF double resonance experiment of rare earth ions in solids. The reso- nance is characterized by a sharp doublepeak structure in the absorption spectrum as the RF frequency is scanned across the hyper® ne transition, with the few kilohertz width of the transparency hole at least an order of magnitude narrower than the spin inhomogeneous width. The ea ect is evident only when the laser bandwidth is larger than the hyper® ne level splittings. A theoretical model is presented based on the assumption that the optical ® elds of a noisy laser simul- taneously couples an optically excited state with two hyper® ne levels of the ground state, which in turn are acted on by the RF ® eld. A quantum interference ea ect among the three coupled transitions creates sharp fringes in the frequency domain that are not averaged out by ensemble average over the inhomogeneousbroadening of the optical or spin transitions. The model is found to be consistent with the main features of the experimental observations. Various quantum interference ea ects in atomic transitions have recently been research topics of great interest, because of the rich and often counter-intuitiveWe have observed kilohertz and sub-kilohertz resonance structures in RF-optical double resonance experiments of rare-earth-doped solids, when the frequency of the RF ® eld is scanned across the hyper® ne transitions while monitoring the resonant optical absorption of a CW laser. The ea ect is observed only when the laser spectral width is broad compared to the hyper® ne structure. The observed line widths are apparently free of the inhomogeneous widths of hyper® ne levels and the line shape has peculiar double peak structure. The ea ect is modelled with a resonance involving three atomic levels interacting with three electromagnetic ® elds, two optical and one RF, in a triangular ordelta' con® guration. While the ordinary optical- RF two-® eld resonance is limited by spin inhomogeneous width, the simul- taneous excitation of three coupled transitions leads to narrow and highly nonlinear resonance structures that are not averaged by the inhomogeneous distribution of hyper® ne transition. We have observed a peculiarly narrow resonance structure in the course of optical-RF double resonance experiment of rare earth ions in solids. The reso- nance is characterized by a sharp doublepeak structure in the absorption spectrum as the RF frequency is scanned across the hyper® ne transition, with the few kilohertz width of the transparency hole at least an order of magnitude narrower than the spin inhomogeneous width. The ea ect is evident only when the laser bandwidth is larger than the hyper® ne level splittings. A theoretical model is presented based on the assumption that the optical ® elds of a noisy laser simul- taneously couples an optically excited state with two hyper® ne levels of the ground state, which in turn are acted on by the RF ® eld. A quantum interference ea ect among the three coupled transitions creates sharp fringes in the frequency domain that are not averaged out by ensemble average over the inhomogeneousbroadening of the optical or spin transitions. The model is found to be consistent with the main features of the experimental observations. Various quantum interference ea ects in atomic transitions have recently been research topics of great interest, because of the rich and often counter-intuitive

Journal of Modern OpticsAug 15, 20003 citations

According to several recent studies, the width of the sharp zero-phonon lines in the electronic spectra of impurities in solids, such as the

R

lines of ruby, is due to Raman scattering of phonons by the impurity ions. The question whether such zero-phonon lines are homogeneously broadened is an important one, both for its own interest and for optical-maser applications. From a detailed study of the stimulated-emission spectra of a ruby laser operating in the traveling-wave modes, we obtain conclusive evidence that such zero-phonon lines are homogeneously broadened. Because the

{R}_{1}

line of ruby is essentially homogeneously broadened at room temperature, the traveling-wave laser oscillates for all practical purposes only in a single mode. The spectral width of the laser emission is extremely sharp. It is less than 0.005 ${\mathrm{cm}}^{\ensuremath{-}1}$ at room temperature as compared to a width of the order of 1 ${\mathrm{cm}}^{\ensuremath{-}1}$ for conventional ruby lasers of comparable intensity. In addition, the output intensity no longer shows random spikes but shows a predictable train of regularly spaced spikes which agree well with theory.