International Business Machines Corporation

Carl Michael Jefferson

John Allen Hoffnagle

Hans J Coufal

Steven Edward Millman

Robert Keith Grygier

Roger F Hoyt

Kenneth Francis Walsh

Hans J&uuml;rgen Coufal

Alfred J Meixner

Maria-Pilar Bernal

Egbert Oesterschoze

Optical devices achromatize the output from a highly efficient refractive laser beam reshaper, thereby allowing collimated, diffraction limited flat-top laser beams to be generated over a wide spectral interval, e.g., over 200 nm in the visible. While the beam reshaper may utilize refractive aspheric lenses, the achromatizers use cost effective spherical refractive elements.

Apparatus for achromatizing optical beams

An optical beam transformation system includes a first and a second optical element, each of which has a non-reentrant surface. The system transforms a substantially non-uniform optical input beam (such as a Gaussian) to a substantially uniform output beam. The first and second optical elements are arranged in either a Keplerian or Galilean configuration. The aspheric surface of the second optical element is related to the aspheric surface of the first optical element by a ray-tracing function that maps substantially all of an input light beam that is incident on the first optical element to a collimated output light beam that is output from the second optical element. Preferably, the output light beam has a Fermi-Dirac intensity distribution, and the ray-tracing function maps the input light beam to the output beam out to the (1/e) intensity radius of the input light beam.

System for converting optical beams to collimated flat-top beams

An optical system having a first positive optical element having an aspherical surface; and a second positive optical element having an aspherical surface. The first and second optical elements are arranged in a Keplerian configuration. The aspheric surface of the second optical element is related to the aspheric surface of the first optical element by a ray-tracing function that maps substantially all of an input light beam that is incident to the first optical element to a collimated output light beam that is output from the second optical element. The input light beam has a first axially-symmetric intensity distribution, such as a Gaussian intensity distribution, and the output light beam has a second axially-symmetric intensity distribution, such as a continuous, sigmoidal intensity distribution. Preferably, the output light beam has a Fermi-Dirac intensity distribution, and the ray-tracing function maps the input light beam to the output beam to a 1/e,intensity radius of the input light beam.

Refractive optical system that converts a laser beam to a collimated flat-top beam

Optical information processor and storage of pixelated data pattern in a Fourier plane of a lens as achieved by a plurality of optical elements operating with a spatial light modulator. A laser light source illuminates a data pattern with a wavefront that is created by a phase mask to effect a phase shift. The optical information can be effecitvely processed or stored, for instance, in a holographic data storage system. The holographic data storage system for storing a data array contains illuminated and dark regions including a multi-fold phase shift mask. This affects a linear and non-random shift of an image. The image is stored on a holographic storage medium. There is a spatial light modulator between the input location for the optical data and the storage medium. The phase shift is effected in the Fourier plane.

Phase shifting element for optical information processing storing systems

Phase modulation is used to record data in a spectral hole burning material. A laser and a phase modulator are used to generate both a reference pulse and a phase modulated data pulse to the material. The data is recorded as spectral holes in the absorption spectrum of the material. In order to read the data, a second reference pulse is generated which creates an echo pulse from the material. This echo pulse is combined with a frequency shifted comparator pulse in order to generate a heterodyne signal. A phase sensitive demodulator detects the phase transitions in the heterodyne signal and generates a digital signal representative of the data recorded.

Spectral hole burning data storage system and method

A self-diagnostic method and apparatus is described for indicating the likelihood of an impending crash of a magnetic transducer or head with a rotating magnetic medium by dynamically and periodically calculating overwrite efficiency for performing a desired control operation when it exceeds a preselected value denoting dangerous proximity of the transducer to the surface of the medium.

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San Jose, CA, United States of America

Carl Michael Jefferson