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Chang-Yuan Han

Bio: Chang-Yuan Han is an academic researcher from Hokkaido University. The author has contributed to research in topics: Gaussian & Wavefront. The author has an hindex of 1, co-authored 1 publications receiving 154 citations.

Papers
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Journal ArticleDOI
TL;DR: A set of holographic filters was developed to convert the Gaussian intensity distribution of a collimated laser beam into a uniform one and experimental results are shown.
Abstract: A set of holographic filters was developed to convert the Gaussian intensity distribution of a collimated laser beam into a uniform one. The design and the fabricating method of the holographic filters are presented and experimental results are shown.

160 citations


Cited by
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Journal ArticleDOI
TL;DR: A system of two aspheric lenses is described, which efficiently converts a collimated Gaussian beam to a flattop beam, and the performance of the as-built optics is compared quantitatively with the theoretical design.
Abstract: A system of two aspheric lenses is described, which efficiently converts a collimated Gaussian beam to a flattop beam. Departing from earlier designs, both aspheric surfaces were convex, simplifying their fabrication; the output beam was designed with a continuous roll-off, allowing control of the far-field diffraction pattern; and diffraction from the entrance and exit apertures was held to a negligible level. The design principles are discussed in detail, and the performance of the as-built optics is compared quantitatively with the theoretical design. Approximately 78% of the incident power is enclosed in a region with 5% rms power variation. The 8-mm-diameter beam propagates approximately 0.5 m without significant change in the intensity profile; when the beam is expanded to 32 mm in diameter, this range increases to several meters.

388 citations

Book
26 Nov 1991
TL;DR: This paper presents a meta-anatomy of holographic interferometry, a branch of imaging that combines Fourier transforms, computer-generated holograms, and other techniques, developed in the 1990s with applications in imaging and other applications.
Abstract: Basics of Holography is a general introduction to the subject written by a leading worker in the field It begins with the theory of holographic imaging, the characteristics of the reconstructed image, and the various types of holograms Practical aspects of holography are then described, including light sources, the characteristics of recording media and recording materials, as well as methods for producing different types of holograms and computer-generated holograms Finally, important applications of holography are discussed, such as high-resolution imaging, holographic optical elements, information processing, and holographic interferometry The book includes comprehensive reference sections and appendices summarizing some useful mathematical results Numerical problems with their solutions are provided at the ends of chapters This is an invaluable resource for advanced undergraduate and graduate students as well as researchers in science and engineering who would like to learn more about holography and its applications in science and industry

161 citations

Journal ArticleDOI
TL;DR: A rigorous electromagnetic diffraction theory is used to evaluate the range of validity of the scalar designs, to analyze fabrication errors, and to design binary resonance-domain one-dimensional array generators with 90%-100% efficiency.
Abstract: Separable binary-phase array illuminators for fan-out up to 1024 x 1024 and ~65% two-dimensional efficiency are designed by simulated annealing with constraints for maximizing the minimum feature size. A new nonseparable trapezoidal coding technique is introduced and applied to design high-efficiency (~75%-80%) array generators for fan-out up to 16 x 16. A rigorous electromagnetic diffraction theory is used to evaluate the range of validity of the scalar designs (both grating period and input angle are considered), to analyze fabrication errors (slanted groove walls and undercutting), and to design binary resonance-domain one-dimensional array generators with 90%-100% efficiency. Trapezoidal gratings for low fan-out (8 x 8), separable gratings for high fan-out (up to 128 x 128), and a 1 x 5 resonance domain (100% efficient) reflection grating are demonstrated experimentally.

146 citations

Patent
Tasso R. M. Sales1
18 Nov 2002
TL;DR: In this paper, the sag profile variations can be used to homogenize an intensity profile of the optical beam and boundary profile variations within an irregular spatial distribution can be applied to apply the prescribed intensity profile within the desired scatter pattern.
Abstract: Microlens array are defined by with microlens (10) elements that differ from each other in accordance with a probability distribution function for shaping an optical beam having a prescribed intensity profile within a desired far-field scatter pattern. The differences include random variations in sag profile corresponding to a surface shape (60) of the micro lenses, a boundary profile (46) corresponding to a boundary of the micro lenses, and a spatial distribution corresponding to the relative position of the micro lenses within the array. The sag profile variations can be used to homogenize an intensity profile of the optical beam. The boundary profile variations within an irregular spatial distribution can be used to apply the prescribed intensity profile of the optical beam within the desired scatter pattern.

109 citations

Journal ArticleDOI
TL;DR: In this paper, a two-element holographic optical system is described for converting an elliptically shaped Gaussian profile laser beam into a rectangularly shaped beam that is uniform in amplitude and phase in the near field.
Abstract: A two-element holographic optical system is described for converting an elliptically shaped Gaussian-profile laser beam into a rectangularly shaped beam that is uniform in amplitude and phase in the nearfield. Theoretical analysis, design considerations, and experimental results are presented for a compact converter system of less than 6 cm in length.

103 citations