| 摘要 |
A zone plate modulator modulates an incident wave by changing the relative distance between a pair of complementary reflective zone plates. The modulator acts to reflect the incident wave as a plane mirror in a first configuration, and to diffract the incident wave into a series of focal points along the axis of the modulator as a phase zone plate in a second con-figuration. A force applied to the zone plates changes the zone plate modulator between the first and second configurations, therefore modulating the incident wave. The force can be an elec-trostatic force generated by a voltage source. An array of zone plate modulator elements is a compact spot array generator performing both the modulating and focusing functions. An achromatic zone plate modulator provides a both wavelength and polarization independent modulation of the incident wave. A variable optical attenuator comprises achromatic zone plate modulators. |
