Integrating Spheres for Mid‐ and Near‐Infrared Reflection Spectroscopy

Hanssen, Leonard M.; Snail, Keith A.

doi:10.1002/0470027320.s2405

Cited by 41 publications

(54 citation statements)

References 42 publications

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“…(3), inevitably causes errors in actual measurements because of the assumptions made in the integrating sphere theory. General error sources for integrating sphere measurements have been identified and well documented [11,12]. In particular, Edwards [11] carefully examined various error sources for center-mount integrating spheres.…”

Section: Resultsmentioning

confidence: 99%

“…The inner wall of the 200-mm-diameter sphere was coated with polytetrafluoroethylene (PTFE), which is a nearly diffuse material with a reflectance of approximately 0.99 in the wavelength region of interest [10]. A center-mount scheme was used in the present study for measurements at various angles of incidence [11,12]. The entrance aperture has a diameter D e = 25 mm.…”

Section: Methodsmentioning

confidence: 99%

“…The view factor from the sphere wall to the detector is denoted by F. If the effects of the baffle, sample, and entrance aperture are neglected, then F = D 2 d /4D 2 sp , where D d and D sp stand for the diameters of the detector and the sphere, respectively [12,14].…”

Section: Methodsmentioning

confidence: 99%

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Measurement and Modeling of the Emittance of Silicon Wafers with Anisotropic Roughness

2007

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The unpolished surface of crystalline silicon wafers often exhibits nonGaussian and anisotropic roughness characteristics, as evidenced by the side peaks in the slope distribution. This work investigates the effect of anisotropy on the emittance. The directional-hemispherical reflectance of slightly and strongly anisotropic silicon wafers was measured at room temperature using a center-mount integrating sphere. A monochromator with a lamp was used for near-normal incidence in the wavelength region from 400-1000 nm, and a continuous-wave diode laser at the wavelength of 635 nm was used for measurements at zenith angles up to 60 • . The directional emittance was deduced from the measured reflectance based on Kirchhoff's law. The geometricoptics-based Monte Carlo model that incorporates the measured surface topography is in good agreement with the experiment. Both the experimental and modeling results suggest that anisotropic roughness increases multiple scattering, thereby enhancing the emittance. On the other hand, if the wafer with strongly anisotropic roughness were modeled as a Gaussian surface with the same roughness parameters, the predicted emittance near the normal direction would be lower by approximately 0.05, or up to 10% at a wavelength of 400 nm. Comparisons also suggest that the Gaussian surface assumption is questionable in calculating the emittance at large emission angles with s polarization, even for the slightly anisotropic wafer. This work demonstrates that anisotropy plays a significant role in the emittance enhancement of rough surfaces. Hence, it is imperative to obtain precise surface microstructure information in order to accurately predict the emittance, a critical parameter for non-contact temperature measurements and radiative transfer analysis. 9180195-928X/07/0600-0918/0

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Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

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Measurement and Modeling of the Emittance of Silicon Wafers with Anisotropic Roughness

2007

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“…The fact that NIR spectra reflect both the chemical and physical nature of the sample often causes offset, wave number, and baseline shifts. Physical effects especially, such as crystallinity, particle size/shape, morphology, and composition, have a considerable effect on the spectra that can be recorded, whether in transmission, diffuse reflection, or transflection mode [81,82]. The characteristic of diffuse reflected light of an irradiated sample is dependent on light scattering within its layers.…”

Section: Near-infrared Diffuse Reflection Spectroscopy Of Carbon Nanomentioning

confidence: 99%

Nanostructured Affinity Surfaces for MALDI‐TOF‐MS–Based Protein Profiling and Biomarker Discovery

Vallant

Rainer

Najam-ul-Haq

et al. 2009

Biosensing Using Nanomaterials

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“…Custom absolute methods have been developed for use with the sphere and are described in detail elsewhere [1,4]. The measurement system includes a sample heater unit that can control sample temperatures between 15 • C and 200 • C. The heater is designed to allow both transmittance and reflectance measurements.…”

Section: Ftis/integrating Sphere Reflectometer Systemmentioning

confidence: 99%

Validation of the Infrared Emittance Characterization of Materials Through Intercomparison of Direct and Indirect Methods

2008

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A comparison of the spectral directional emittance of samples as a function of wavelength was performed at the Fourier Transform Infrared Spectrophotometry (FTIS) and the Advanced Infrared Radiometry and Imaging (AIRI) facilities at NIST. At the FTIS, the emittance is obtained indirectly through the measurement of near-normal directional-hemispherical reflectance (DHR) using an infrared integrating sphere. At the AIRI, the normal directional emittance is obtained directly through the measurement of the sample spectral radiance referenced to that from blackbody sources, while the sample is located behind a black plate of known temperature and emittance. On the same setup at the AIRI, the normal emittance at near ambient temperatures is also measured indirectly by a "two-temperature" method in which the sample spectral radiance is measured while the background temperature is controlled and varied. The sample emittance measurements on the comparison samples are presented over a wavelength range of 3.4 µm to 13.5 µm at several near-ambient temperatures and for near-normal incidence. The results obtained validate the two independent capabilities and demonstrate the potential of the controlled background methods for measurements of the radiative properties of IR materials.

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Integrating Spheres for Mid‐ and Near‐Infrared Reflection Spectroscopy

Abstract: The sections in this article are Introduction Terminology Historical Review Theory of Sphere Throughput Reflectance Techniques Absolute Reflectance Methods Relative Reflectance Methods Dealing with Error Sources: Sphere Design Considerations … Show more

Cited by 41 publications

References 42 publications

Measurement and Modeling of the Emittance of Silicon Wafers with Anisotropic Roughness

Measurement and Modeling of the Emittance of Silicon Wafers with Anisotropic Roughness

Nanostructured Affinity Surfaces for MALDI‐TOF‐MS–Based Protein Profiling and Biomarker Discovery

Validation of the Infrared Emittance Characterization of Materials Through Intercomparison of Direct and Indirect Methods

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