High-reflectivity HfO_2/SiO_2 ultraviolet mirrors

Torchio, Philippe; Gatto, Alexandre; Alvisi, Marco; Albrand, G.; Kaiser, Norbert; Amra, Claude

doi:10.1364/ao.41.003256

Cited by 87 publications

(31 citation statements)

References 7 publications

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“…In addition, at this temperature, a very small amount of SiO 2 , in the form of cristobalite, has been detected (Fig.2). This could be explained by an initial formation of amorphous silica which then transforms to cristobalite above 1200 o C [5]. The HfO 2 coatings were subjected to re-entry tests up to 100 cycles at 1450 o C. These tests showed no flaking-off of the coatings.…”

Section: Resultsmentioning

confidence: 99%

Thermo-Mechanical Behaviour of HfO<sub>2</sub> Coatings for Aerospace Applications

Mergia

Liedtke²,

Speliotis

et al. 2008

AMR

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Abstract. The use of ceramic composite materials in aerospace applications requires the development of oxidization protection coatings which can withstand very high temperatures. HfO 2 is a promising material as a high temperature oxidization protective layer. HfO 2 coatings have been deposited by radiation frequency magnetron sputtering all over the surface of SiC substrates and were tested under re-entry conditions. Also their oxidization resistance in air in the temperature range 1100 to 1450°C has been examined. The coatings were found to be stable and well-adhering to the substrate even after 100 re-entry cycles. No oxidization of the underlying SiC structure is observed. Re-entry and oxidization tests result in the formation of HfSiO 4 at the HfO 2 /SiC interface, which further promotes their oxidization resistance.

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Section: Resultsmentioning

confidence: 99%

Thermo-Mechanical Behaviour of HfO<sub>2</sub> Coatings for Aerospace Applications

Mergia

Liedtke²,

Speliotis

et al. 2008

AMR

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“…The effective length λ is given by λ Z(3) /n b , where λ Z (3) is the resonant wavelength of the Z 3 exciton in vacuum, and n b is the background refractive index. The values of n b for CuCl, HfO 2 , and SiO 2 are 2.36, 16 2.05, 17 and 1.50, 17 respectively. The thicknesses of the HfO 2 and SiO 2 layers in the DBR were designed as λ/4.…”

Section: Methodsmentioning

confidence: 96%

Control of exciton-photon interactions in CuCl microcavities

et al. 2011

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We have investigated the active-layer-thickness dependence of exciton-photon interactions in planar CuCl microcavities with HfO 2 /SiO 2 distributed Bragg reflectors. The active layer thickness was changed from λ/32 to λ/4, while the cavity length was fixed at λ/2. We performed angle-resolved reflectance measurements and clearly detected three cavity-polariton modes, originating from the lower, middle, and upper polariton branches, in a strong-coupling regime of the Z 3 and Z 1,2 excitons and cavity photon. The incidence-angle dependence of the cavity-polariton modes was analyzed using a phenomenological Hamiltonian for the strong coupling. It was found that the interaction energies of the cavity-polariton modes, the so-called vacuum Rabi splitting energies, are systematically controlled from 22(37) to 71(124) meV for the Z 3 (Z 1,2 ) exciton by changing the active layer thickness from λ/32 to λ/4. The active-layer-thickness dependence of the Rabi splitting energy is quantitatively explained by a simple theory for quantum-well microcavities.

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“…HfO 2 is preferred for optical devices such as optical filters, high-reflectivity mirrors, high power lasers and other optoelectronic devices because of its desirable properties such as high refractive index, high laser damage threshold and high transparency in the visible and ultraviolet (UV) spectral ranges [1][2][3][4][5]. Because of its outstanding chemical stability, electrical and mechanical properties, high-dielectric constant and wide band gap, hafnium dioxide (HfO 2 ) has been considered as one of the most important materials with a wide range of potential scientific and technological applications in electronics [6,7], magneto-electronics [8,9], optoelectronics [10] and metal oxide semiconductor devices [11].…”

Section: Introductionmentioning

confidence: 99%