<i>Introduction to the Luminescence of Solids</i>

Leverenz, H. W.; Urbach, Frank

doi:10.1063/1.3067011

Cited by 116 publications

(59 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…While some of the compounds listed in Table 3 have been known as fluorescent materials for some time [10,11], this does not necessarily mean that they are useful as scintillators because (i) some compounds have radiative transitions that are excited much more efficiently by UV radiation than by x-rays and (ii) some compounds exhibit a fluorescence after UV or x-ray excitation that originates only from the surface and photons produced by excitation deep in the crystal (such as by gamma radiation) are absorbed in the bulk of the crystal by radiation trapping and lost by non-radiative processes. For this reason, many powders listed in Table 1 require further study in crystal form before they can be established as useful scintillators.…”

Section: Fluorescent Lifetimes and Wavelengthsmentioning

confidence: 99%

Prospects for new inorganic scintillators

Derenzo

Moses

Cahoon

et al. 1990

IEEE Trans. Nucl. Sci.

109

View full text Add to dashboard Cite

[ [ ) . frJ r;y;)Prepared for the U.S. Department of Energy under Contract Number DE-AC03-76SF00098..... DISCLAIMERThis document was prepared as an account of work sponsored by the United States Government. While this document is believed to contain correct information, neither the United States Government nor any agency thereof, nor the Regents of the University of California, nor any of their employees, makes any warranty, express or implied, or assumes any legal responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by its trade name, trademark, manufacturer, or otherwise, does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof, or the Regents of the University of California. ABSTRACTAlthough scintillation has been discovered in many inorganic crystals during the past 40 years, there is continued interest in finding compounds with improved scintillation properties. However, the testing of candidate compounds has thus far been limited to those available as crystals of suitable quality and size. We describe a method using synchrotron x-radiation for measuring the fluorescence properties of powders, which makes accessible a much larger number of compounds. We present results for 85 compounds tested by this method. Scintillation from several compounds was discovered, notably CeF3 and PbC03.

show abstract

Section: Fluorescent Lifetimes and Wavelengthsmentioning

confidence: 99%

Prospects for new inorganic scintillators

Derenzo

Moses

Cahoon

et al. 1990

IEEE Trans. Nucl. Sci.

109

View full text Add to dashboard Cite

show abstract

“…One way to achieve green laser action from an Erdoped material is by using upconversion. Upconversion lasers operate through the excitation of a higherlying state either by absorption of multiple lowerenergy pump photons [5] or by cooperative upconversion due to dipole-dipole interaction between excited ions [6]. Rare-earth-doped glasses are ideal hosts for upconversion lasers due to the relatively long lifetimes of the 4f manifolds.…”

mentioning

confidence: 99%

On-chip green silica upconversion microlaser

et al. 2009

View full text Add to dashboard Cite

We demonstrate an erbium-doped silica toroidal microcavity upconversion laser on a silicon chip lasing in the visible spectral range ͑510-580 nm͒. The microcavity is pumped at 1458 nm by a tapered optical fiber coupled to the cavity and the lasing threshold is 690 W. Lasing is observed at room temperature despite the high nonradiative relaxation rates of Er in pure silica that usually precludes upconversion lasing from higher excited states. This is attributed to the very high circulating pump power in the high-Q microcavity ͑Q Ͼ 10 7 ͒. One way to achieve green laser action from an Erdoped material is by using upconversion. Upconversion lasers operate through the excitation of a higherlying state either by absorption of multiple lowerenergy pump photons [5] or by cooperative upconversion due to dipole-dipole interaction between excited ions [6]. Rare-earth-doped glasses are ideal hosts for upconversion lasers due to the relatively long lifetimes of the 4f manifolds. A large effort has been put into engineering Er-doped glasses with minimal phonon energies and hence long excitedstate lifetimes. Indeed, green upconversion lasing has been observed in ZrF 4 -BaF 2 -LaF 3 -AlF 3 -NaF (ZBLAN) compound glasses [7][8][9], where Klitzing et al. [10] have reported a green upconversion laser with a threshold power as low as 30 W using a ZBLAN microsphere as the resonant cavity.The ZBLAN material, however, is incompatible with Si processing technology. Pure silica, on the other hand, has proven to be an excellent material to fabricate on-chip microcavities [11,12], but so far, the short excited-state manifold lifetime that results from the relatively high phonon energy in silica has precluded the observation of upconversion lasing in such cavities. In this Letter, we demonstrate a way to circumvent this limitation of the excited-state transition level in a silica host by using a resonant cavity with an extremely high quality factor ͑Q Ͼ 10 7 ͒. The resonator device is fabricated on a silicon wafer enabling integration of the green lasing emission with optoelectronic functionality on the same chip.Er-doped silica microcavities were fabricated on Si substrates using a sol-gel process [11,12]. The typical toroid major and minor diameters measured 40 and 4 m, respectively. The inset of Fig. 1(a) shows a scanning electron microscope image of an Er-doped toroidal microcavity. The typical Er concentration in the cavity is estimated to be 0.1-0.5 at. %. The typical intrinsic quality factor of these Er-doped cavities [4] is well above 10 7 . For a toroidal cavity with an intrinsic quality factor of Q =5ϫ 10 7 a pump power of 10 mW coupled into the cavity will build up a circulating power as high as 1 kW. This circulating power is concentrated into a cross sectional area of only several square micrometers, giving rise to an intensity that can exceed 1 GW/ cm 2 . As will be demonstrated below, such high intracavity intensities are sufficient to create population inversion of higher-lying excited states of Er 3+ , which is otherwise d...

show abstract

“…The emission band is assigned to transitions between the spin-orbit components of the 4 T 1 excited state and the 6 A1 ground state. 2,15,17,18 Figure 5 shows the PL spectra of Zn 1.92 Mn 0.08 SiO 4 prepared at different temperature between 800 o C and 1200 o C. All emission spectra were obtained under 254 nm excitation. The PL spectra show that the PL intensity of the Zn 1.92 Mn 0.08 SiO 4 phosphor increases as the synthetic temperature increases.…”

Section: Resultsmentioning

confidence: 99%