journal menu
![[Figure 1]](mo5178fig1mag.jpg)
|
|
Figure 1
Zone plates modulate the phase and magnitude of a transmitted wave so as to direct it to a focus. This can be done in several ways, using magnitude and/or phase modulations on alternating zones of half-wavelength optical path difference to the focus. A simple Fresnel zone plate (a) has an outermost zone width of drN and a thickness t; it applies a constant magnitude reduction or phase shift across each zone, while a blazed zone plate (b) puts a staircase approximation of a phase ramp across the zone. One can stack several thin Fresnel zone plates (c) to manipulate the wave at several locations leading to the focus, or use thicker zones (d) which are individually tilted to meet the Bragg grating condition or even curved in a volume hologram approach to produce the converging wavefield. |
![[Figure 1]](mo5178fig1.jpg)
 | JOURNAL OF SYNCHROTRON RADIATION |
ISSN: 1600-5775
access
