From HoloWiki - A Holography FAQ
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| **a ≈ 2b | | **a ≈ 2b |
| **T = λ/(n-1) ± 10% | | **T = λ/(n-1) ± 10% |
− | **Surface shadows reduce D.E. by <math>\lambda^2 / n d^2</math> [[Image:Equ1.gif]] | + | **Surface shadows reduce D.E. by <math>\textstyle \frac{\lambda^2}{n d^2}</math> |
− | **Wavelength changes reduce D.E. by <math>(\pi\Delta\lambda / b\lambda)^2/</math> [[Image:Equ2.gif]] | + | **Wavelength changes reduce D.E. by <math>\scriptstyle \left(\frac{\pi\Delta\lambda}{b\lambda}\right)^2</math> |
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| *Φ = wedge angle of glass | | *Φ = wedge angle of glass |
| *Special case of linear scan and near wobble invariance a ~ b ~ 45° max straight scan angle ~ 36° | | *Special case of linear scan and near wobble invariance a ~ b ~ 45° max straight scan angle ~ 36° |
− | *Dynamic wobble <math>\simeq \Delta\Omega/128</math> | + | *Dynamic wobble <math>\scriptstyle \simeq \Delta\Omega/128</math> |
| *Wedge wobble = (n-1)Φ | | *Wedge wobble = (n-1)Φ |
| *Scan angle multiplier = 1.4 @ 90° cross scan angle | | *Scan angle multiplier = 1.4 @ 90° cross scan angle |
Revision as of 15:05, 12 May 2013
Common DOE surfaces
Sinusoidal, triangle
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- Max D.E. ~ 30% ± 1 order
- Power distribution follows Bessel function in the scaler region.
- T ≈ λ for transmission.
- T ≈ λ/4 for reflection.
- Easily replicated or deep etch can yield higher efficiency.
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Square, rectangle
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- Max D.E. ~ 40% ± 1 order.
- Power distributions favors odd orders.
- Pi phase shift typical.
- Classic binary grating.
- T ≈ λ for transmission.
- T ≈ λ/4 for reflection.
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Blazed, sawtooth
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- Max D.E ~ 98%
- Reflection Case:
- λ = 2 d sin a
- T = λ/2 ± 10%
- Transmission Case:
- λ = d sin b
- a ≈ 2b
- T = λ/(n-1) ± 10%
- Surface shadows reduce D.E. by Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle \textstyle \frac{\lambda^2}{n d^2}}
- Wavelength changes reduce D.E. by Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle \scriptstyle \left(\frac{\pi\Delta\lambda}{b\lambda}\right)^2}
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Holographic Deflectors (hologons)
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- N = θD/(1.4λ)
- N = number of resolvable spots
- θ = full scan angle in radians
- D = beam diameter in microns
- λ = wavelength
- Φ = wedge angle of glass
- Special case of linear scan and near wobble invariance a ~ b ~ 45° max straight scan angle ~ 36°
- Dynamic wobble Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle \scriptstyle \simeq \Delta\Omega/128}
- Wedge wobble = (n-1)Φ
- Scan angle multiplier = 1.4 @ 90° cross scan angle
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Last modified on 9/29/97