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           omnidirectional reflector and microcavity resonator via the sol-gel method

Chen, Kevin; Sparks, Andrew W.; Luan, Hsin-Chiao; Lim, Desmond R.; Wada, Kazumi; Kimerling, Lionel C.

doi:10.1063/1.125462

Cited by 150 publications

(83 citation statements)

References 10 publications

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“…In addition, optical devices, including buried-channel erbium-doped waveguide amplifiers, microlenses, one-dimensional photonic crystal devices and external-cavity distributed Bragg reflector ͑DBR͒ laser have been achieved using the sol-gel method. [6][7][8][9] Here we report a new method to fabricate both erbium-doped microlasers and Raman microlasers on a silicon chip using sol-gel films as the base material for microtoroid formation. In one series of experiments, erbium-doped sol-gel films are used to create low threshold microlasers.…”

mentioning

confidence: 99%

Erbium-doped and Raman microlasers on a silicon chip fabricated by the sol–gel process

Yang¹,

Carmon²,

Min³

et al. 2005

Applied Physics Letters

143

117

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We report high-Q sol-gel microresonators on silicon chips, fabricated directly from a sol-gel layer deposited onto a silicon substrate. Quality factors as high as 2.5ϫ 10 7 at 1561 nm were obtained in toroidal microcavities formed of silica sol-gel, which allowed Raman lasing at absorbed pump powers below 1 mW. Additionally, Er 3+ -doped microlasers were fabricated from Er 3+ -doped sol-gel layers with control of the laser dynamics possible by varying the erbium concentration of the starting sol-gel material. Continuous lasing with a threshold of 660 nW for erbium-doped microlaser was also obtained. Recently, a chip-based silica resonator structure in the form of a microtoroid has demonstrated ultrahigh-Q-factors in the range of 100 million. 1 By coating these high-Q microcavities with erbium-doped sol-gel films 2 or by beginning with erbium implanted silica layers, 3 low threshold rareearth-doped microlasers on-a-chip have been demonstrated. In another study, the realization of integrated Raman microlasers beginning with a layer of thermally-grown silica has been achieved. 4 Microlasers on silicon chips are especially interesting because they are integrable with other optical or electric components. In this work, we demonstrate the possibility of making microlasers directly from the sol-gel layers on the silicon wafer. The sol-gel method for preparing silica and silicate from a metal alkoxide precursor provides a versatile and cost-effective way to fabricate various components on silicon chips. It combines control of composition and microstructure at the molecular level with the ability to shape materials in bulk, fiber, powder, and thin film forms. 5 This technique allows a wide variety of thin films to be deposited on various substrates. In addition, optical devices, including buried-channel erbium-doped waveguide amplifiers, microlenses, one-dimensional photonic crystal devices and external-cavity distributed Bragg reflector ͑DBR͒ laser have been achieved using the sol-gel method. 6-9 Here we report a new method to fabricate both erbium-doped microlasers and Raman microlasers on a silicon chip using sol-gel films as the base material for microtoroid formation. In one series of experiments, erbium-doped sol-gel films are used to create low threshold microlasers. In a second set of experiments, pure silica sol-gel layers are processed into ultrahigh-Q Raman microlasers. Both of these cases demonstrate the ability to use spin coating of sol-gel films as a processing alternative to deposition or oxidation methods for silica layer formation.The sol-gel solution was prepared by hydrolyzing tetraethoxysilane ͑TEOS͒ using water with the molar ratio of water to TEOS around 1-2. Hydrochloric acid was added to make the solution in acid condition. Er 3+ ions were introduced by adding Er͑NO͒ 3 to achieve the desired Er 3+ concentration. After reaction at 70°C for 3 h, a viscous solution was formed. The silica sol-gel film was then deposited on a silicon substrate by the spin-coating method. Different thicknesses of the s...

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mentioning

confidence: 99%

Erbium-doped and Raman microlasers on a silicon chip fabricated by the sol–gel process

Yang¹,

Carmon²,

Min³

et al. 2005

Applied Physics Letters

143

117

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“…In this work, we have developed a procedure to extract the exact density profile of sol-gel films, and applied it to analyze a sol-gel derived Er 2 Sol-gel films have been widely investigated for optical applications due to their very low cost and fast preparation process. 1,2 Layered films of different density and thickness can easily produce waveguides for visible light [3][4][5][6][7] as well as for hard x rays. 8 In high-brilliance synchrotron radiation sources, x-ray waveguides have become an important optical device that can lead to new developments in x-ray microscopy 9 and characterization techniques with submicroscale resolution.…”

mentioning

confidence: 99%

Nanostructure of sol–gel films by x-ray specular reflectivity

Morelhão¹,

Brito²,

Abramof

2002

Applied Physics Letters

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Recently, several studies have been carried out on sol–gel films for optical applications, mostly motivated by the quickness and low cost of the film preparation process. In order to preserve the coherence properties of the light, improvements in the current quality of such films are necessary as well as appropriated techniques for structural characterization and quality control. X-ray specular reflectivity could be one of such techniques, but it is limited by the complexity of the internal nanostructure of the films. In this work, we have developed a procedure to extract the exact density profile of sol–gel films, and applied it to analyze a sol–gel derived Er2O3 film.

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“…The minimum of transmittance (λ 0 ), the width, and the amplitude of the optical band are determined by stack contrast among all transparent metal oxides. [9][10][11] Despite the good optical quality of such dielectric mirrors (e.g., up to ≈82% reflectance at λ 0 in the visible region for four double layers), they do require extremely high calcination temperatures of 300-900 °C. Accordingly, special ovens as well as heat stable substrates are essential.…”

Section: Introductionmentioning

confidence: 99%

Printing of Large‐Scale, Flexible, Long‐Term Stable Dielectric Mirrors with Suppressed Side Interferences

Bronnbauer

Riecke

Adler

et al. 2017

Advanced Optical Materials

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Dielectric mirrors are wavelength‐selective mirrors which are based on thin film interference effects. Their optical band can precisely be adjusted in width, position, and reflectance by the refractive index of the applied materials, the layers' thicknesses, and the amount of deposited layers. Nowadays, they are a well‐known light management tool for efficiency enhancement in, for example, semitransparent organic solar cells (OSCs) and light guiding in organic light‐emitting diodes (OLEDs). However, most of the dielectric mirrors are still fabricated by lab‐scale techniques such as spin‐coating or physical vapor deposition under vacuum. Large‐scale, fully printed (maximum 20 × 20 cm2) dielectric mirrors with adjustable reflectance characteristics are fabricated, using temperatures of maximum 50 °C and alcohol‐based inks. According to the moderate processing conditions they can be easily deposited not only on rigid glass substrates but also on flexible foils. They show high stability against humidity, light irradiation, and temperature, positioning themselves as good candidates for applications in OLEDs and OSCs. Eventually, by simulations and experiments it is verified that a moderate degree of variations in layer thickness and surface roughness can suppress side interference fringes, while not impacting the main transmittance minimum or the main reflection maximum, respectively.

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SiO 2 / TiO 2 omnidirectional reflector and microcavity resonator via the sol-gel method

Cited by 150 publications

References 10 publications

Erbium-doped and Raman microlasers on a silicon chip fabricated by the sol–gel process

Erbium-doped and Raman microlasers on a silicon chip fabricated by the sol–gel process

Nanostructure of sol–gel films by x-ray specular reflectivity

Printing of Large‐Scale, Flexible, Long‐Term Stable Dielectric Mirrors with Suppressed Side Interferences

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