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For many
applications, the value of holography to deliver a practical optical
solution depends upon the ability to record an exact hologram of
the desired complex wavefront. Photopolymer media offer a number
of favorable attributes, including:
- Imaging amplification
- High refractive
index modulation
- Robust, permanent
recording
- Flexibility to choice
of recording wavelength
- Flexibility of media
form factor
- Ease of manufacturing
- Material cost
Unfortunately,
most photopolymers suffer from several detractions, including:
- Significant volume
shrinkage
- Sensitivity to oxygen/air
- Reduction of performance
at low spatial frequency
Most
of these problems are directly related to the choice of free radical
chemistry for the imaging mechanism. STX Aprilis has avoided the problems
of free radical chemistry while retaining the value of photopolymer
media solutions by using cationic ring opening polymerization (CROP)
for its imaging chemistry. STX Aprilis media have consistently shown
significantly improved recording sensitivity and dynamic range over
free radical-based media, when compared under conditions that produce
comparable (low) volume shrinkage.
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