&lt;title&gt;Optical properties of diamond&lt;/title&gt;

Thomas, Michael E.; Tropf, William J.

doi:10.1117/12.187336

Cited by 18 publications

(33 citation statements)

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“…High-quality such as type IIA optical diamonds are transparent from the farinfrared up to the ultraviolet photon energy region, [8] except for the multiphonon absorption bands located at ω = 0.19 − 0.34 eV. [10] Moreover, they have a large refractive index n d ≈ 2.4 which shows only 10% energy dependence up to ω ≈ 5 eV. [6,7,8,9, 10] The significant difference between the refractive index of the two reference media is a crucial point of the method.…”

Section: Pacs Numbersmentioning

confidence: 99%

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An alternative of spectroscopic ellipsometry: The double-reference method

Kézsmárki

Bordács

2008

Applied Physics Letters

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We have developed a conceptually new type of ellipsometry which allows the determination of the complex refractive index by simultaneously measuring the unpolarized normal-incidence reflectivity relative to the vacuum and to another reference media. From these two quantities the complex optical response can be directly obtained without Kramers-Kronig transformation. Due to its transparency and large refractive index over a broad range of the spectrum, from the far-infrared to the soft ultraviolet region, diamond can be ideally used as a second reference. The experimental arrangement is rather simple compared to other ellipsometric techniques. PACS numbers:Determination of the complex dielectric response of a material is an everlasting problem in optical spectroscopy. Depending on the basic optical properties, whether the sample is transparent or has strong absorption in the photon-energy range of interest, its absolute reflectivity or the transmittance is usually detected with normal incidence. Both quantities are related to the intensity of the light and give no information about the phase change during either reflection or transmission. Consequently, the phase shift is generally determined by Kramers-Kronig (KK) transformation in order to obtain the complex dielectric response. However, for the proper KK analysis the reflectivity or the transmittance spectrum has to be measured in a broad energy range, ideally over the whole electromagnetic spectrum.On the other hand, there exist ellipsometric methods [1,2] which are capable to simultaneously detect both the intensity and the phase of the light reflected back or transmitted through a media. Among them the most state-of-the-art technique is the time domain spectroscopy but its applicability is mostly restricted to the far infrared region. [3,4] An other class of ellipsometric techniques, sufficient for broadband spectroscopy, requires polarization-selective detection of light. [1,2] (In the following we will discuss experimental situations in reflection geometry although most of the considerations are valid for transmission, as well.) A representative example is the so-called rotating-analyzer ellipsometry (RAE) when the reflectivity is measured at a finite angle of incidence, usually in the vicinity of the Brewster angle. [1,2] Under this condition the Fresnel coefficients are different for polarization parallel (p-wave) and perpendicular (s-wave) to the plane of incidence and the initially linearly polarized light becomes elliptically polarized upon the reflection. By rotating the analyzer the ellipsometric parameters, i.e. the phase difference and the intensity ratio for the p-wave and s-wave components of the reflected light, [5] are measured and the complex refractive index can be directly obtained. Each of the above experimental methods is far more complicated than the measurement of unpolarized reflectivity or transmittance near normal incidence.As an alternative, we describe a new type of ellipsometry, hereafter referred to as double-reference spectrosc...

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Section: Pacs Numbersmentioning

confidence: 99%

“…[6,7,8,9,10] Although the Fresnel equations are highly nonlinear,n s can easily be expressed in the lack of absorption within the diamond, i.e. for k d ≡ 0:…”

Section: Pacs Numbersmentioning

confidence: 99%

An alternative of spectroscopic ellipsometry: The double-reference method

Kézsmárki

Bordács

2008

Applied Physics Letters

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“…This analysis fails only for the multiphonon absorption bands of the diamond located in the range of = 1500-2700 cm −1 . 15 We note at this point that, additional to the absorption of the diamond above Ϸ 40 000 cm −1 , the high-energy limit of this method is determined by the roughness and/or planarity of the diamondsample interface ␦ ds . Therefore, special care should be taken for the proper matching between the window and the sample in order to eliminate interference and diffraction effects inherently appearing for wavelength shorter than ␦ ds .…”

Section: Methodsmentioning

confidence: 99%

“…The R vd ͑ ͒ / ͓1−R vd ͑ ͔͒ 2 prefactor can be calculated from the well-documented refractive index of diamond n d . 10,[12][13][14][15] High-quality, such as type IIA, optical diamonds show no significant absorption up to Ϸ 40 000 cm −1 . On the other hand, the effect of weak absorption introduces only another frequency-dependent factor into Eq.…”

Section: Methodsmentioning

confidence: 99%

High-pressure infrared spectroscopy: Tuning of the low-energy excitations in correlated electron systems

et al. 2007

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We have extended the range of the high-pressure optical spectroscopy to the far-infrared region keeping the accuracy of ambient-pressure experiments. The developed method offers a powerful tool for the study of pressure-induced phase transitions and electronic-structural changes in correlated electron systems as the optical pressure cell, equipped with large free-aperture diamond window, allows the measurement of optical reflectivity down to Ϸ 20-30 cm −1 for hydrostatic pressures up to p Ϸ 26 kbar. The efficiency of the technique is demonstrated by the investigation of the two-dimensional charge-density-wave 1T-TaS 2 whose electronic structure shows high sensitivity to external pressure. The room-temperature semimetallic phase of 1T-TaS 2 is effectively extended by application of pressure and stabilized as the ground state above p = 14 kbar. The corresponding fully incoherent low-energy optical conductivity is almost temperature independent below T = 300 K. For intermediate pressures, the onset of the low-temperature insulating phase is reflected by the sudden drop of the reflectivity and by the emergence of sharp phonon resonances.

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“…Harsh environment applications have been extensively studied and the high corrosion stability of NCD electrodes was confirmed [2,9]. Additionally, diamond can be either insulating or quasi-metallic and has an extended range of transparency (225 nm-12 μm) [10] due to its wide bandgap semiconductor characteristics. NCD microelectrode and ultra-microelectrode arrays have been also widely studied and used in the fields of electro-analysis and life science [11][12][13][14].…”

Section: Introductionmentioning

confidence: 99%

Fabrication of a NCD microelectrode array for amperometric detection with micrometer spatial resolution

Colombo

Men

Scharpf

et al. 2011

Diamond and Related Materials

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We report on the fabrication of a boron-doped nanocrystalline diamond (NCD) 3 × 3 high-density microelectrode array (MEA) for amperometric measurements, with a single electrode area of 3 × 5 μm 2 and a separation in the μm scale. The NCD microelectrodes were grown by hot filament chemical vapor deposition (HFCVD) on a double-side polished sapphire wafer in order to preserve the diamond transparency. Bias enhanced nucleation (BEN) was performed to ensure a covalent adhesion of the films to the substrate. A current background noise of less than 5 pA peak to peak over a 1 kHz bandwidth resulted from an electrochemical investigation of the new device, using 100 mM KCl solutions and ferrocyanide red-ox couples. Cyclic voltammetry measurements in physiological buffer solution and in the presence of oxidizable biomolecules strengthened its suitability for bio-sensing. When compared to a 2 × 2 NCD microelectrode array prototype, already used for in vitro cell measurements, the signal to noise ratio of the amperometric response of the new 3 × 3 device proved twice as good. In addition, the optical transmittance of the boron-doped thin layers exceeded 40% in the visible wavelength range. The excellent electrochemical properties of NCD electrodes and the transparency in combination with the high spatial resolution make the new 3 × 3 NCD MEA a promising tool for electrochemical sensing in a variety of applications, ranging from medical to industrial, in neutral or harsh environments.

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<title>Optical properties of diamond</title>

Cited by 18 publications

References 0 publications

An alternative of spectroscopic ellipsometry: The double-reference method

An alternative of spectroscopic ellipsometry: The double-reference method

High-pressure infrared spectroscopy: Tuning of the low-energy excitations in correlated electron systems

Fabrication of a NCD microelectrode array for amperometric detection with micrometer spatial resolution

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