Dismiss
InnovationQ will be updated on Sunday, Oct. 22, from 10am ET - noon. You may experience brief service interruptions during that time.
Browse Prior Art Database

Exposure of Holograms On Low Optical Quality Substrates

IP.com Disclosure Number: IPCOM000103299D
Original Publication Date: 1990-Sep-01
Included in the Prior Art Database: 2005-Mar-17
Document File: 1 page(s) / 45K

Publishing Venue

IBM

Related People

Fortenberry, RS: AUTHOR

Abstract

The single beam method for copying a holographic optical element (HOE) from a master hologram generally involves immersing the copy substrate in index matching fluid, positioning the master hologram on top of the copy substrate, and illuminating the master hologram with a reference laser beam. The resulting diffracted beam interferes with the undiffracted portion of the reference beam to form the copy hologram on the copy substrate.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 84% of the total text.

Exposure of Holograms On Low Optical Quality Substrates

      The single beam method for copying a holographic optical
element (HOE) from a master hologram generally involves immersing the
copy substrate in index matching fluid, positioning the master
hologram on top of the copy substrate, and illuminating the master
hologram with a reference laser beam.  The resulting diffracted beam
interferes with the undiffracted portion of the reference beam to
form the copy hologram on the copy substrate.

      If the copy substrate is of low optical quality (Mylar, for
instance) and the copy hologram will not be encapsulated in an index
matching adhesive, then the above technique can result in aberrations
of the diffracted laser beam when the HOE is played back.  This
disclosure describes an exposure technique that will reduce the
read-out beam aberration, improving the performance of the HOE.

      The aberration occurs because the index matching fluid masks
the out-of-flat condition of the substrate.  When the copy hologram
is read in air, the read beam "sees" the actual surface shape.  The
read condition no longer matches the record condition, and
aberrations result.

      By anti-reflection coating the master hologram and eliminating
the index matching fluid, the read-out conditions match the record
conditions more closely.  The performance of the holographic optical
element is improved accordingly.

      Note that the condition of the bottom surface...