Cryogenic high-accuracy absolute prism refractometer for infrared through far-ultraviolet optical materials: implementation and initial results

Frey, Bradley J.; Henry, Ross; Leviton, Douglas B.; Quijada, Manuel A.

doi:10.1117/12.506097

Cited by 10 publications

(14 citation statements)

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“…Typical day-to-day repeatability 1 ; absolute nearly 2-3x better. measurement accuracy for this material is 1·10 -5 .…”

Section: Plot Indexmentioning

confidence: 98%

“…From that table, a new table of spectral dispersion, dn/dλ, is computed by dividing differences in index value, n, by corresponding differences in wavelength, λ, for each temperature. Thermo-optic coefficient, dn/dT, is simply the first derivative of n(T) with respect to T or dn(T)/dT = 2 c 2 T + c 1 . CDC produces a table of thermo-optic coefficients on that same regular wavelength and temperature grid.…”

Section: Fit Index(t)mentioning

confidence: 99%

“…in vacuum) of optical materials over a wide range of environmental conditions. CHARMS currently measures absolute refractive index from 0.4 µm to 5.6 µm in wavelength and at temperatures as low as 15 K. This system has been under development for more than four years and our incremental development has been previously documented 1,2,3 . The intention of this text is to summarize the improvements made to the system hardware and to describe the automated data acquisition and data reduction processes.…”

Section: Introductionmentioning

confidence: 99%

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Automation, operation, and data analysis in the cryogenic, high accuracy, refraction measuring system (CHARMS)

Frey

Leviton

2005

SPIE Proceedings

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The Cryogenic High Accuracy Refraction Measuring System (CHARMS) at NASA's Goddard Space Flight Center has been enhanced in a number of ways in the last year to allow the system to accurately collect refracted beam deviation readings automatically over a range of temperatures from 15 K to well beyond room temperature with high sampling density in both wavelength and temperature. The engineering details which make this possible are presented. The methods by which the most accurate angular measurements are made and the corresponding data reduction methods used to reduce thousands of observed angles to a handful of refractive index values are also discussed.

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“…Typical day-to-day repeatability 1 ; absolute nearly 2-3x better. measurement accuracy for this material is 1·10 -5 .…”

Section: Plot Indexmentioning

confidence: 98%

Section: Fit Index(t)mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Automation, operation, and data analysis in the cryogenic, high accuracy, refraction measuring system (CHARMS)

Frey

Leviton

2005

SPIE Proceedings

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“…Measurement methods used and recent facility improvements are discussed in a companion paper. 2 , and LiF). The prisms (which rest on the surface of a flat mirror) are illuminated near minimum deviation with a collimated beam of white light coming from the lower left corner of the photo.…”

Section: Introductionmentioning

confidence: 99%

“…1,2,3 For low index materials with only modest dispersion such as synthetic fused silica, CHARMS can measure absolute index with an uncertainty in the sixth decimal place of index. For materials with higher indices and high dispersion such as CVD ZnSe, CHARMS can measure absolute index with an uncertainty of about 1 part in the fourth decimal place of index.…”

Section: Introductionmentioning

confidence: 99%

High accuracy, absolute, cryogenic refractive index measurements of infrared lens materials for JWST NIRCam using CHARMS

2005

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The refractive optical design of the James Webb Space Telescope (JWST) Near Infrared Camera (NIRCam) uses three infrared materials in its lenses: LiF, BaF 2 , and ZnSe. In order to provide the instrument's optical designers with accurate, heretofore unavailable data for absolute refractive index based on actual cryogenic measurements, two prismatic samples of each material were measured using the cryogenic, high accuracy, refraction measuring system (CHARMS) at NASA's Goddard Space Flight Center (GSFC), densely covering the temperature range from 15 to 320 K and wavelength range from 0.4 to 5.6 microns. Data reduction methods are discussed and graphical and tabulated data for absolute refractive index, dispersion, and thermo-optic coefficient for these three materials are presented for selected wavelengths and temperatures along with estimates of index uncertainty. Coefficients for temperature-dependent Sellmeier fits of measured index are also presented with an example of their usage to predict absolute index at any wavelength or temperature within the applicable range of those parameters.

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Temperature-dependent refractive index measurements of S-FPL51, S-FTM16, and S-TIM28 to cryogenic temperatures

2013

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Cryogenic high-accuracy absolute prism refractometer for infrared through far-ultraviolet optical materials: implementation and initial results

Cited by 10 publications

References 0 publications

Automation, operation, and data analysis in the cryogenic, high accuracy, refraction measuring system (CHARMS)

Automation, operation, and data analysis in the cryogenic, high accuracy, refraction measuring system (CHARMS)

High accuracy, absolute, cryogenic refractive index measurements of infrared lens materials for JWST NIRCam using CHARMS

Temperature-dependent refractive index measurements of S-FPL51, S-FTM16, and S-TIM28 to cryogenic temperatures

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