Tunable optical filter actuator

A tunable optic filter 10 has means for receiving input radiation beams 40a and transmitting output radiation beams 40b. Actuation means are provided in order to move the filter means 10 relative to the beam for selecting a portion of the filtering means 10 in order to tune the filter 10. The actuation means include one or more actuating elements 70a - 70d operable to repetitively engage and thereby impart a lateral force to a surface of the filter 10 in order to move the filter 10 relative to the beam. The filter may also have a support member and be configured in a partial or complete annulus (see figure 9) where the actuating elements 70a - 70d operate to rotationally actuate the support member relative to the input beam for tuning the filter 10. The actuation elements 70a - 70d can generate the lateral force by employing piezoelectric, magnetostatic, electrostatic or thermal expansion effects and can be in the form of silicon micromachined components. In the figure a filter plate 20 is surrounded by an optical region 30 and spacing members 60a, 60b. Exterior plates 50a, 50b together with alignment apertures 80a, 80b are also shown. A method of tuning an optical filter is also disclosed.