Related Experiment Video
Updated: Jul 6, 2026
10:39
Measurement of X-ray Beam Coherence along Multiple Directions Using 2-D Checkerboard Phase Grating
Published on: October 11, 2016
Secondary grating formation by readout at Bragg-null incidence
Applied Optics
|March 8, 2008
Summary
Reading dynamic holograms at Bragg nulls creates secondary gratings, altering selectivity. This unintended recording can cause significant cross talk in multiplexed holograms, especially with high diffraction efficiencies.
Area of Science:
- Holography
- Optical data storage
- Photorefractive materials
Background:
- Holographic data storage relies on recording and retrieving information using holograms.
- Multiplexing techniques increase data capacity but can introduce cross talk.
- Dynamic holograms and Bragg selectivity are key concepts in holographic storage.
Purpose of the Study:
- To investigate the impact of reading dynamic holograms at Bragg nulls on grating recording.
- To analyze the formation of secondary gratings and their effect on selectivity curves.
- To evaluate the resulting cross talk in multiplexed holographic systems.
Main Methods:
- Recording dynamic holograms in a suitable medium.
- Illuminating the recorded hologram at the Bragg null angles.
- Analyzing the diffracted beams and the formation of secondary gratings.
- Experimentally verifying the predicted effects on selectivity and cross talk.
Main Results:
- Illumination at Bragg nulls leads to the recording of two secondary gratings.
- These secondary gratings modify the selectivity curve of the original hologram.
- The effect causes significant cross talk, potentially exceeding interpage cross talk in specific multiplexing scenarios.
Conclusions:
- Dynamic hologram readout at Bragg nulls introduces an artifactual grating recording.
- This artifact can degrade the performance of multiplexed holographic storage systems.
- Careful consideration of readout conditions is necessary to minimize unwanted cross talk.
Related Concept Videos
02:18X-ray Crystallography
The size of the unit cell and the arrangement of atoms in a crystal may be determined from measurements of the diffraction of X-rays by the crystal, termed X-ray crystallography.
Diffraction
Diffraction is the change in the direction of travel experienced by an electromagnetic wave when it encounters a physical barrier whose dimensions are comparable to those of the wavelength of the light. X-rays are electromagnetic radiation with wavelengths about as long as the distance between neighboring...
Diffraction
Diffraction is the change in the direction of travel experienced by an electromagnetic wave when it encounters a physical barrier whose dimensions are comparable to those of the wavelength of the light. X-rays are electromagnetic radiation with wavelengths about as long as the distance between neighboring...
01:29Determination of Crystal Structures
In the late 1800s, the revelation that light extended beyond visible wavelengths led to the discovery of X-rays by Wilhelm Roentgen. Recognized as high-energy electromagnetic radiation with short wavelengths, X-rays prompted exploration into their interaction with crystals. Max von Laue proposed in 1912 that the periodic arrangement of atoms, ions, or molecules in crystals would cause them to diffract X-rays, a hypothesis confirmed through experiments with copper sulfate and zinc sulfide...