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Journal ArticleDOI

Reshaping collimated laser beams with Gaussian profile to uniform profiles.

15 Nov 1983-Applied Optics (Optical Society of America)-Vol. 22, Iss: 22, pp 3644-3647
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.
Citations
More filters
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

References
More filters
Book ChapterDOI
Wai-Hon Lee1
TL;DR: The computer-generated holograms have their greatest potential in the area of interferometry and have been shown to be useful in supplementing existing methods of optical testing.
Abstract: Publisher Summary This chapter describes the techniques and applications of computer-generated holograms. “Computer-generated holograms,” “synthetic holograms,” and “computer holograms” are terms used to refer to a class of holograms that are produced as graphical output from a digital computer. Given a mathematical description of a wavefront or an object represented by an array of points, the computer can calculate the amplitude transmittance of the hologram and display the result on a CRT or plot it on paper. Using photoreduced copy of the graphical output from a computer as holograms is only one of the many things that distinguish computer generated holograms from conventional ones. The computer-generated holograms have their greatest potential in the area of interferometry. They have been shown to be useful in supplementing existing methods of optical testing. Laser beam scanning is another promising area for computer-generated holograms. Holographic grating scanners are in many ways better than other mechanical mirror scanners.

266 citations

Journal ArticleDOI
TL;DR: A set of differential equations is derived which specifies the shape of two aspherical surfaces of a lens system that will convert an incident plane wave with an arbitrary energy profile into collimated radiation with a uniform energy distribution.
Abstract: A set of differential equations is derived which specifies the shape of two aspherical surfaces of a lens system that will convert an incident plane wave with an arbitrary energy profile into collimated radiation with a uniform energy distribution. As an example, a lens system is designed that converts a laser beam with a Gaussian energy profile into an expanded beam with a uniform energy distribution. Off-axis rays are then traced through the lenses in order to analyze the performance of the lens system.

194 citations

Journal ArticleDOI
TL;DR: A new CO(2) laser beam profile shaper was designed and tested, with high-power efficiency, that transforms a fundamental mode laserbeam profile into a flattop profile at a focal plane.
Abstract: A new CO2 laser beam profile shaper was designed and tested. With high-power efficiency, it transforms a fundamental mode laser beam profile into a flattop profile at a focal plane. The shaper uses an interlaced binary diffraction grating that modulates the E field both in phase and amplitude and generates an apodized and clipped sinc(x) distribution in the object plane.

121 citations

Journal ArticleDOI
TL;DR: The beam shaper the authors developed shapes the transmit beam of a CO(2) laser radar that uses a linear detector array and produces a stretched profile that efficiently and uniformly illuminates the far-field footprint of the detector array.
Abstract: The beam shaper we developed shapes the transmit beam of a CO(2) laser radar that uses a linear detector array. It consists of a diffraction grating and an anamorphic prism beam compressor and produces a stretched profile that efficiently and uniformly illuminates the far-field footprint of the detector array. The diffraction grating phase modulates the near field or the laser beam to generate a far-field flattop intensity profile, whereas the compressor produces the necessary profile eccentricity. We have achieved conversion efficiencies in the 70-90% range.

91 citations