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- Ekberg, Mats, 1961, et al.
(författare)
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Multilevel phase holograms manufactured by electron-beam lithography
- 1990
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Ingår i: Optics Letters. - 0146-9592 .- 1539-4794. ; 15, s. 568-569
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Tidskriftsartikel (refereegranskat)abstract
- Ten-level transmission phase holograms (kinoforms) manufactured in one resist layer by electron-beam lithography are reported for the first time to the authors' knowledge. The measured hologram diffraction efficiencies were 70% for the two resist materials used. This corresponds to 82% of the maximum theoretical value for these holograms and is, to the authors' knowledge, the highest reported to date
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4. |
- Karlsson, Magnus, 1967, et al.
(författare)
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Dynamics of self-focusing and self-phase modulation in a parabolic index optical fiber.
- 1992
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Ingår i: Optics Letters. - 0146-9592 .- 1539-4794. ; 17:1, s. 22-24
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Tidskriftsartikel (refereegranskat)abstract
- The dynamics that result from the combined effects of spatial diffraction, nonlinearity, and a parabolic graded index for wave propagation in optical fibers are presented. An approximate analytical solution of the nonlinear Schrödinger equation in a graded-index fiber is obtained by using a variational approach. Particular emphasis is put on the variation of both the pulse width and the longitudinal phase delay with the distance of propagation along the fiber.
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6. |
- Andersson-Engels, Stefan, et al.
(författare)
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Multispectral Tissue Characterization With Time-resolved Detection of Diffusely Scattered White-light
- 1993
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Ingår i: Optics Letters. - 0146-9592. ; 18:20, s. 1697-1699
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Tidskriftsartikel (refereegranskat)abstract
- A novel technique for the noninvasive measurement of tissue optical properties simultaneously at all visible and near-infrared wavelengths is presented. The technique is based on.the time-resolved detection of multicolor diffusely scattered light. Short pulses of white light are/produced by using self-phase modulation by focusing the light from a short-pulsed high-power laser into a cuvette filled with water. After spectral dispersion in a polychromator and temporal dispersion in a streak tube, a two-dimensional CCD camera was used as a detector, with one dimension used for time resolution and the other one for wavelength separation.
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8. |
- Kauranen, P, et al.
(författare)
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Tomographic imaging of fluid flows by the use of two-tone frequency-modulation spectroscopy
- 1994
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Ingår i: Optics Letters. - 0146-9592. ; 19:18, s. 1489-1491
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Tidskriftsartikel (refereegranskat)abstract
- Diode laser absorption measurements obtained with two-tone frequency-modulation spectroscopy (TTFMS) are combined with tomography to produce spatially resolved quantitative images of fluid flows. The high sensitivity, good accuracy, and high stability of TTFMS absorption measurements permit optical-absorption tomography to be performed with low noise on extremely weakly absorbing objects. The method is demonstrated on a small oxygen flow with a GaAlAs diode laser operating near 760 nm and with an absorption sensitivity of 1:106.
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9. |
- Kröll, Stefan, et al.
(författare)
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Photon-echo-based logical processing
- 1993
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Ingår i: Optics Letters. - 0146-9592. ; 18:21, s. 1834-1836
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Tidskriftsartikel (refereegranskat)abstract
- Word-by-word logical AND and OR operation with photon-echo processing is demonstrated for what is to our knowledge the first time. The photon-echo process can store sequences of optical data before processing. The present logical operations on 8- and 4-bit words are performed by using single-shot frequency-chirped photon echoes. Data rates of approximately 1 MHz, input energies of 1-10 nJ/bit, and output energies in the picojoule-per-bit range are demonstrated by using a transition with a transition probability of only 20 s(-1).
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10. |
- Xu, E. Y, et al.
(författare)
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Nanosecond image processing using stimulated photon echoes
- 1990
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Ingår i: Optics Letters. - 0146-9592. ; 15:10, s. 562-564
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Tidskriftsartikel (refereegranskat)abstract
- Processing of two-dimensional images on a nanosecond time scale is demonstrated using the stimulated photon echoes in a rare-earth-doped crystal (0.1 at. \% Pr3$+$:LaF3). Two spatially encoded laser pulses (pictures) resonant with the 3P0-3H4 transition of Pr3$+$ were stored by focusing the image pulses sequentially into the Pr3$+$:LaF3 crystal. The stored information is retrieved and processed by a third read pulse, generating the echo that is the spatial convolution or correlation of the input images. Application of this scheme to high-speed pattern recognition is discussed.
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