Refraction index change measurement
AssigneeHoneywell Inc.
InventorRalph T. Berg
Life of this patent
Estimating the term…
Abstract
A method and apparatus for measuring the change in refractive index of a material with respect to temperature. The invention contemplates measuring the change in length of the material with respect to temperature over a predetermined temperature range with a Fizeau Interferometer by measuring the change in length through a vacuum at a point adjacent the length to produce a first set of data. Also measured is the change in the same length of the same material with respect to temperature over the same predetermined temperature range with the Interferometer by measuring the change in the length through the material to produce a second set of data. Determining the difference between the first and second sets of data produces resulting data which is the change in refractive index of the material with respect to temperature.
Claims11
A method of measuring the change in refractive index of a material as a function of temperature, said method comprising the steps of:
- determining a first change in length of a selected length-wise dimension of a test sample of a selected material in response to a selected temperature change, said first change in length determined as a function of a first optical path followed by an optical beam passing through a vacuum, substantially in parallel with said length-wise dimension, and wherein said first optical path is affected by said length-wise dimension of said test sample;
- determining a second change in length of said selected length-wise dimension of said test sample in response to said selected temperature change as a function of a second optical path followed by an optical beam passing through said test sample materials, substantially in parallel with said length-wise dimension of said test sample;
- and
- determining the change in said index of refraction for said selected temperature change as a function of the difference between said first change in length and said second change in length.
A method of measuring the change in refractive index of a material with respect to temperature, comprising the steps of:
- determining a first change in length of a selected length-wise dimension of a test sample of a selected material with respect to temperature over a pre-determined temperature range with a Fizeau interferometer by measuring said change in length as a function of a first optical path followed by an optical beam passing through a vacuum, substantially in parallel with said length-wise dimension, and wherein said first optical path is affected by said length-wise dimension of said test sample in order to produce a first set of data;
- determining a second change in length of said length-wise dimension of said test sample in response to said pre-determined temperature range with said Fizeau interferometer by measuring said second change in length as a function of a second optical path followed by an optical beam passing through said test sample material, substantially in parallel with said length-wise dimensions, and wherein said second optical path is affected by said length-wise dimensions of said test sample in order to produce a second set of data;
- and
- determining a change in said index of refraction for said selected temperature range as a function of the difference between said first change in length and said second change in length.
A method of measuring the change in refractive index of a material as a function of temperature comprising the steps of:
- determining a first change in length of a selected length-wise dimension of a test sample of a selected material in response to a selected temperature change by employing the use of a Fizeau interferometer in which Newton interference rings are established, at least in part, as a function of an optical beam propagating along an optical path, through a vacuum, and between first and second plates which define said length-wise dimension of said test sample;
- determining a second change in length of said selected length-wise dimension of said test sample in response to said selected temperature change by employing the use of said Fizeau interferometer in which Newton interference rings are established, at least in part, as a function of an optical beam propagating along an optical path through said test sample material, between first and second end surfaces of said test sample which define said length-wise dimension of said test sample, and substantially in parallel with said length-wise dimensions and
- determining the change in said index of refraction for said temperature change as a function of the difference between said first change in length and said second change in length.
Dependencies are inferred from the claim text.