Multiple probe actuation

The method of any preceding claim further comprising:

• a. directing a detection input beam into an optical device;
• b. transforming the detection input beam with the optical device into a plurality of output beamlets which are not parallel with each other;
• c. splitting each output beamlet into a sensing beamlet and an associated reference beamlet;
• d. simultaneously directing each of the sensing beamlets onto an associated one of the probes to generate a reflected beamlet;
• e. combining each reflected beamlet with its associated reference beamlet to generate an interferogram;
• and
• f. measuring each interferogram to determine the position of an associated one of the probes.

Actuation apparatus for actuating a plurality of probes, the apparatus comprising:

• a beam source for generating an input beam;
• an optical device arranged to receive the input beam and transform the input beam to generate an actuation beam which is output from the optical device at an output angle;
• and a controller arranged to operate the optical device to modulate the output angle of the actuation beam over time so that the actuation beam is sequentially directed onto the probes thereby delivering energy to the probes so that the probes deform relative to a sample, wherein the energy is delivered to the probes by sequentially illuminating them with the actuation beam in a series of scan sequences, wherein two or more of the probes are illuminated by the actuation beam in each scan sequence;
• and the controller is arranged to operate the optical device and/or the beam source and/or an optical element in a path of the actuation beam or in a path of the input beam so that different amounts of energy are delivered to at least two of the probes by the actuation beam during at least one of the scan sequences.