Production of bright, wideband white light from Y2O3 nano-powders induced by laser diode emission

Bílír, Gökhan; Bartolo, Baldassare Di

doi:10.1016/j.optmat.2014.03.027

Cited by 39 publications

(27 citation statements)

References 15 publications

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“…3(a) and (b) show the WL spectrum collected in the 400-900 nm wavelength range of the samples Y 2 O 3 : Nd (20%) and Y 2 O 3 : Nd (0%), corresponding to the highest (20%) and lowest (0%) Nd 3þ content, respectively, under excitation at 803.5 nm with pumping power of 2 W and various environment temperatures. Some of our preliminary results on WL emitted by infrared excited un-doped metal oxide nano-powders have been reported elsewhere [24], [25]. The WL spectra under examination were emitted by samples with crystallite size of 26 nm.…”

Section: Results Of the 8035 Nm Excitationmentioning

confidence: 91%

Unconventional Production of Bright White Light Emission by Nd-Doped and Nominally Un-Doped <inline-formula> <tex-math notation="TeX">$\hbox{Y}_{2}\hbox{O}_{3}$</tex-math></inline-formula> Nano-Powders

et al. 2014

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We report the production of a broad band (ranging from 400 to 900 nm) white light following the monochromatic infrared light (803.5 and 975 nm) excitation of both nominally un-doped and Nd 3þ -doped Y 2 O 3 nano-powders, even up to 20% of Nd 3þ content. Experimental results indicate that such emission feature is a nano-scale phenomenon, cannot be ascribed to an overlap of sharp emission bands in the un-doped case and, even if assisted by the Nd 34 presence, is a host matrix-related process. The measured white light emission is strongly dependent on either environment pressure (a pressure threshold occurs) or pumping power. The rising patterns of the white light emission were found to increase faster for either increasing Nd 3þ content and pumping power or decreasing particle size. Notably, high correlated color temperature (2756 K), color rendering index (99), and efficiency (864 lx/W) values were measured for the un-doped sample under 803.5 nm exciting wavelength.

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Section: Results Of the 8035 Nm Excitationmentioning

confidence: 91%

Unconventional Production of Bright White Light Emission by Nd-Doped and Nominally Un-Doped <inline-formula> <tex-math notation="TeX">$\hbox{Y}_{2}\hbox{O}_{3}$</tex-math></inline-formula> Nano-Powders

et al. 2014

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“…Since then, the white emission has been observed in rare earth doped nanocrystalline powders, ceramic, glasses and bulk crystals, as investigated by several groups1011121314151617181920. The bright white emission was also reported for undoped nanocrystalline powders by the Di Bartollo group212223.…”

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confidence: 91%

Laser induced white lighting of graphene foam

Stręk¹,

Tomala²,

Łukaszewicz³

et al. 2017

Sci Rep

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Laser induced white light emission was observed from porous graphene foam irradiated with a focused continuous wave beam of the infrared laser diode. It was found that the intensity of the emission increases exponentially with increasing laser power density, having a saturation level at ca. 1.5 W and being characterized by stable emission conditions. It was also observed that the white light emission is spatially confined to the focal point dimensions of the illuminating laser light. Several other features of the laser induced white light emission were also discussed. It was observed that the white light emission is highly dependent on the electric field intensity, allowing one to modulate the emission intensity. The electric field intensity ca. 0.5 V/μm was able to decrease the white light intensity by half. Origins of the laser-induced white light emission along with its characteristic features were discussed in terms of avalanche multiphoton ionization, inter-valence charge transfer and possible plasma build-up processes. It is shown that the laser-induced white light emission may be well utilized in new types of white light sources.

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“…For example, the white light intensity was measured to be ∼5 times stronger at vacuum pressure than at atmospheric pressure at an excitation power of 4 Watts. The peaks observed in the low-pressure spectrum correspond to emission transitions of Er 3+ : 4 24 at low pressure in Er 2 O 3 . The color temperature of Er 2 O 3 nano-crystalline powder at room and vacuum condition under 4 Watts of 975 nm infrared excitation were measured to be 2467 K and 2281 K, respectively.…”

Section: Partially-doped Nano-powdersmentioning

confidence: 89%

Broadband, White Light Emission from Doped and Undoped Insulators

Tabanli

Cinkaya

Bílír

et al. 2017

ECS J. Solid State Sci. Technol.

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We present data on broadband, white light emission from insulating hosts under intense excitation in the near infrared in host materials that are undoped, partially-doped with rare earth ions, and that contain stoichiometric concentrations of rare earth ions. Much of the emission is found to have a blackbody-like structure in the visible and near infrared region. The origin of the emission as from a blackbody is also supported by the temporal characteristics of the emission in response to turning on and off the laser, and also by the dependence of the air pressure in the chamber. However, some of the data presented cannot be explained by blackbody emission alone, so other processes are proposed to explain the observed spectra. The role of the rare earth ion dopants in enhancing the broadband emission is also considered. Over the last several years, numerous works have reported a broadband, white-light emission from insulating powders under intense, near infrared (IR) excitation. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19] The materials investigated are usually nano-powders of insulators, such as yttrium oxide, yttrium silicate, Al 2 O 3 , GGG, and others, either pure or doped with rare earth ions (e.g. Er, Nd, Yb, Tm) or transition metal ions (e.g. Cr). Spectral and temporal characteristics of the broadband emission suggest that it is thermal in origin. One study on the origin of the emission, conducted by Debasu et al.,16 concluded that the emission is indeed blackbody emission, with temperatures in the range of ∼1200 K-1900 K. We have studied the white-light emission phenomenon in several host materials, both doped and undoped. In this work, we present results representative of this body of work, and we consider how these results fit into the blackbody model.For lighting applications, one of the main goals is the generation of high quality, white light with highest possible efficiency. Broadband white light based on blackbody-like emission can be of very high quality, but it is never efficient, especially compared to compact fluorescent or LED-based lighting. The white light we report on here is probably no different in that regard, and so it likely will be of little usefulness as a general lighting source. One difference between these emitters and tungsten-based blackbody sources is the means by which energy is delivered to the system; the energy source is a near infrared diode laser instead of electrical power converted to Joule heating, as in a tungsten lamp.Production of white light using near IR photons can occur in different ways. One method of recent interest is the upconversion process in rare earth doped systems that depend on energy transfer and/or excited state absorption to produce emission of high-energy photons. Usually, this occurs in systems co-doped with, for example, Yb, Er and Tm, 20,21 and the emission is exclusively from the f-f transitions of the dopant ions. The white light reported on here is generated in a fundamentally different way. The energy contained in the...

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Production of bright, wideband white light from Y2O3 nano-powders induced by laser diode emission

Cited by 39 publications

References 15 publications

Unconventional Production of Bright White Light Emission by Nd-Doped and Nominally Un-Doped <inline-formula> <tex-math notation="TeX">$\hbox{Y}_{2}\hbox{O}_{3}$</tex-math></inline-formula> Nano-Powders

Unconventional Production of Bright White Light Emission by Nd-Doped and Nominally Un-Doped <inline-formula> <tex-math notation="TeX">$\hbox{Y}_{2}\hbox{O}_{3}$</tex-math></inline-formula> Nano-Powders

Laser induced white lighting of graphene foam

Broadband, White Light Emission from Doped and Undoped Insulators

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