Back to results
US 7,312,875 B2Granted
Two-wavelength spatial-heterodyne holography
AssigneeUT-Battelle, LLC
InventorsGregory R. Hanson, Philip R. Bingham, John T. Simpson, Thomas P. Karnowski, Edgar Voelkl
Life of this patent
Estimating the term…
Abstract
Systems and methods are described for obtaining two-wavelength differential-phase holograms. A method includes determining a difference between a filtered analyzed recorded first spatially heterodyne hologram phase and a filtered analyzed recorded second spatially-heterodyned hologram phase.
Claims8
A method of obtaining a differential-phase spatially-heterodyned hologram at a beat wavelength defined by a first wavelength and a second wavelength, comprising:
- digitally recording a first spatially-heterodyned hologram at the first wavelength, the first spatially-heterodyned hologram including spatial heterodyne fringes for Fourier analysis;
- and substantially simultaneously
- digitally recording a second spatially-heterodyned hologram at the second wavelength that is different from the first wavelength, the second spatially-heterodyned hologram including spatial heterodyne fringes for Fourier analysis;
- then
- Fourier analyzing the recorded first spatially-heterodyned hologram by shifting a first original origin of the recorded first spatially-heterodyned hologram including spatial heterodyne fringes in Fourier space to sit on top of a spatial-heterodyne carrier frequency defined as a first angle between a first reference beam and a first object beam;
- Fourier analyzing the recorded second spatially-heterodyned hologram by shifting a second original origin of the recorded second spatially-heterodyned hologram including spatial heterodyne fringes in Fourier space to sit on top of a spatial-heterodyne carrier frequency defined as a second angle between a second reference beam and a second object beam, the first angle and the second angle not substantially equal;
- applying a first digital filter to cut off signals around the first original origin and performing an inverse Fourier transform on the result;
- applying a second digital filter to cut off signals around the second original origin and performing an inverse Fourier transform on the result;
- and then
- determining a difference between a filtered analyzed recorded first spatially heterodyne hologram phase and a filtered analyzed recorded second spatially-heterodyned hologram phase.
7 more elements
A method of obtaining a differential-phase spatially-heterodyned hologram at a beat wavelength defined by a first wavelength and a second wavelength, comprising:
- digitally recording a first spatially-heterodyned hologram at the first wavelength, the first spatially-heterodyned hologram including spatial heterodyne fringes for Fourier analysis;
- Fourier analyzing the recorded first spatially-heterodyned hologram by shifting a first original origin of the recorded first spatially-heterodyned hologram including spatial heterodyne fringes in Fourier space to sit on top of a spatial-heterodyne carrier frequency defined as a first angle between a first reference beam and a first object beam;
- digitally recording a second spatially-heterodyned hologram at the second wavelength that is different from the first wavelength, the second spatially-heterodyned hologram including spatial heterodyne fringes for Fourier analysis;
- Fourier analyzing the recorded second spatially-heterodyned hologram by shifting a second original origin of the recorded second spatially-heterodyned hologram including spatial heterodyne fringes in Fourier space to sit on top of a spatial-heterodyne carrier frequency defined as a second angle between a second reference beam and a second object beam;
- applying a first digital filter to cut off signals around the first original origin and performing an Inverse Fourier transform on the result;
- applying a second digital filter to cut off signals around the second original origin and performing an inverse Fourier transform on the result;
- and then
- determining a difference between a filtered analyzed recorded first spatially-heterodyned hologram phase and a filtered analyzed recorded second spatially-heterodyned hologram phase.
5 more elements
A method of obtaining a differential-phase hologram at a beat wavelength defined by a first wavelength and a second wavelength, comprising:
- digitally recording a first spatially-heterodyned hologram at the first wavelength, the first spatially-heterodyned hologram including spatial heterodyne fringes for Fourier analysis;
- digitally recording a second spatially-heterodyned hologram at the second wavelength that is different from the first wavelength, the second spatially-heterodyned hologram including spatial heterodyne fringes for Fourier analysis;
- Fourier analyzing the recorded first spatially-heterodyned hologram by shifting a first original origin of the recorded first spatially-heterodyned hologram including spatial heterodyne fringes in Fourier space to sit on top of a spatial-heterodyne carrier frequency defined as a first angle between a first reference beam and a first object beam;
- applying a first digital filter to cut off signals around the first original origin and performing and inverse Fourier transform on the result;
- Fourier analyzing the recorded second spatially-heterodyned hologram by shifting a second original origin of the recorded second spatially-heterodyned hologram including spatial heterodyne fringes in Fourier space to sit on top of a spatial-heterodyne carrier frequency defined as a second angle between a second reference beam and a second object beam;
- applying a second digital filter to cut off signals around the second original origin and performing and inverse Fourier transform on the result;
- and then
- determining a difference between a filtered analyzed recorded first spatially heterodyne hologram phase and a filtered analyzed recorded second spatially-heterodyned hologram phase;
- wherein digitally recording the first spatially-heterodyned hologram at the first wavelength is completed before digitally recording the second spatially-heterodyned hologram.
6 more elements
Dependencies are inferred from the claim text.