Optical Design Of An Integrating Sphere-Fourier Transform Spectrophotometer (FTS) Emissometer

1986 ◽  
Author(s):  
Keith A. Snail ◽  
Kevin F. Carr
Keyword(s):  
Fourier Transform ◽  
Optical Design ◽  
Integrating Sphere

Fourier Transform Reflectance Spectrometry between 8000 cm−1 (1.25 μm) and 800 cm−1 (12.5 μm) Using an Integrating Sphere

1983 ◽  
Vol 37 (1) ◽  
pp. 32-38 ◽  
Author(s):  
W. Richter
Keyword(s):  
Fourier Transform ◽  
Integrating Sphere ◽  
Angle Of Incidence ◽  
Spectral Measurements ◽  
Hemispherical Reflectance ◽  
Infrared Spectral ◽  
High Purity Silicon ◽  
Silicon And Germanium ◽  
Main Components ◽  
Absolute Reflectance

Spectral measurements of the directional hemispherical reflectance of samples exhibiting variant reflection behavior were performed in the near and mid infrared spectral region using the integrating sphere method. The main components of the experimental setup were a sphere with a diffuse gold coating and a commercial Fourier transform spectrometer for the spectral analysis of the radiation incident on and reflected by the sample which is located in the center of the sphere. The capability of the device to measure absolute reflectances was tested with polished slices of high purity silicon and germanium, the reflectances of which can be calculated from the refractive indices. Agreement between the measured and calculated values was found to be within 0.01. Diffuse reflectance standards are not yet available in the infrared. The uncertainty of absolute reflectance measurements is estimated to be ±0.02. Several examples of chemical and technical applications are presented. A relatively low spectral resolution, 16 cm−1, was used to keep the measurement times short, within the range of a few minutes, thereby minimizing signal drifts. Higher resolution, sometimes necessary for special purposes in chemical analysis, can be attained by longer measurement times. No extensive sample preparation and adjustment is necessary besides the choice of the desired angle of incidence.

On Fourier's Phase and Gradient Index Optical Design

1994 ◽  
Vol 374 ◽  
Author(s):  
Peter D. Haaland
Keyword(s):  
Refractive Index ◽  
Fourier Transform ◽  
Constrained Optimization ◽  
Phase Modulation ◽  
Fourier Transforms ◽  
Optical Design ◽  
Optical Filters ◽  
Gradient Index ◽  
Design Objective ◽  
The Relationship

AbstractGradient index or rugate optical filters are continuous generalizations of the familiar quarterwave stack which find widespread applications in sensor hardening. In the design of a filter or mirror there are infinitely many refractive index profiles n(x) whose wavelength-dependent reflectance R(λ) is specified as a design objective. The relationship between R(λ) and n(x) is nearly that of a Fourier-transform pair. Exploiting this relationship, specifically the physically indeterminate phase of the Fourier transforms, permits constrained optimization of rugate designs. In this contribution we outline the approach of optimal phase modulation and indicate by examples its application to problems in optical limiting.

Emissivity of Wavelength-Selective Radiator With Periodic Microcavities

2013 ◽  
Author(s):  
Tsuyoshi Totani ◽  
Minoru Iwata ◽  
Masashi Wakita ◽  
Harunori Nagata
Keyword(s):  
Fourier Transform ◽  
Gold Film ◽  
Fourier Transform Infrared ◽  
Integrating Sphere ◽  
Micro Structure ◽  
Emissive Power ◽  
Periodic Microstructure ◽  
Ultraviolet Curable ◽  
Infrared Spectrometer ◽  
Normal Emissivity

A periodic microstructure of the cubic cavity 6.0 μm wide, 6.0 μm deep, and 6.0 μm high is built on an ultraviolet curable resin via UV nanoimprinting. The 200 nm thick gold film is sputtered on the periodic micro structure. The hemispherical spectroscopic transmittance and reflectance of the periodic microstructure with the gold film are measured using a Fourier transform infrared spectrometer with an integrating sphere. The hemispherical spectroscopic transmittance is 0.0 from 2 to 15 μm wavelength. The hemispherical spectroscopic reflectance is 1.0 from 2 to 8 μm wavelength and from 12 to 15 μm wavelength. The bottom of the hemispherical spectroscopic reflectance is 0.4 near 10 μm. Assuming Kirchhoff’s law, the maximum normal emissivity of the periodic microstructure is 0.6 near 10 μm. It is clarified that the periodic microcavities with a gold film built via UV nanoimprinting and sputtering can enhance maximum spectral emissive power of radiation.

scholarly journals Reflectometers for Absolute and Relative Reflectance Measurements in the Mid-IR Region at Vacuum

Sensors ◽  
2021 ◽  
Vol 21 (4) ◽  
pp. 1169
Author(s):  
Jinhwa Gene ◽  
Min Yong Jeon ◽  
Sun Do Lim
Keyword(s):  
Fourier Transform ◽  
Diffuse Reflectance ◽  
Standard Uncertainty ◽  
Integrating Sphere ◽  
The Third ◽  
Systematic Uncertainties ◽  
Infrared Spectrometer ◽  
Reflecting Surfaces ◽  
Absolute Reflectance ◽  
Reflectance Measurements

We demonstrated spectral reflectometers for two types of reflectances, absolute and relative, of diffusely reflecting surfaces in directional-hemispherical geometry. Both are built based on the integrating sphere method with a Fourier-transform infrared spectrometer operating in a vacuum. The third Taylor method is dedicated to the reflectometer for absolute reflectance, by which absolute spectral diffuse reflectance scales of homemade reference plates are realized. With the reflectometer for relative reflectance, we achieved spectral diffuse reflectance scales of various samples including concrete, polystyrene, and salt plates by comparing against the reference standards. We conducted ray-tracing simulations to quantify systematic uncertainties and evaluated the overall standard uncertainty to be 2.18% (k = 1) and 2.99% (k = 1) for the absolute and relative reflectance measurements, respectively.

Optical Design of Fourier Transform Lens for Measurement of Illumination Pupil of Lithography Tools

2015 ◽  
Vol 42 (4) ◽  
pp. 0416001
Author(s):  
蔡燕民 Cai Yanmin ◽  
王向朝 Wang Xiangzhao ◽  
步扬 Bu Yang ◽  
黄惠杰 Huang Huijie
Keyword(s):  
Fourier Transform ◽  
Optical Design

Optical Design Of The ATMOS Fourier Transform Spectrometer

1979 ◽  
Author(s):  
Irving R. Abel ◽  
Bruce R. Reynolds ◽  
J. B. Breckinridge ◽  
J. Pritchard
Keyword(s):  
Fourier Transform ◽  
Optical Design ◽  
Fourier Transform Spectrometer
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