Abstract: An inertial positioner comprising a base plate and a carriage plate (2) slidably connected to one another via a bearing assembly (3) so as to allow relative movement of the plates in a positioning direction. The bearing assembly (3) comprises two sets of caged ball bearings seated in respective pairs of V-grooves (25 and 26) formed in the facing surfaces of the base and carriage plates, the V-groove pairs extending spaced apart in the positioning direction. An actuator comprising a piezoelectric element (4) and a rod (5) extends between the plates (1 and 2), the piezoelectric element (4) being secured to the carriage plate (2) and the rod (5) forming a frictional engagement characterized by a force F with the base plate via a collar (20) fastened to the base plate via biasing means (not shown). In operation, a periodic saw-tooth voltage is applied to the piezoelectric element (4) to produce motion.

Abstract: A method and apparatus for determining the optical aperture diameter `d` of tips suitable for use in near-field scanning optical microscopy (NSOM). Several functional relationships are found between the far-field angular intensity distribution function I(.theta.) for light of wavelength `.lambda.` emitted out of the aperture, the angle `.theta.` being that formed between the direction of travel of the photon concerned and the perpendicular to the plane of the aperture. It is found that I(.theta.) depends sensitively on the aperture `d`. In one embodiment tip diameters can be measured for diameters in the range of .lambda./6<d<.lambda..

Abstract: A scanning probe microscope, in particular for near-field scanning optical, friction force and atomic force microscopy, comprises a tip piece attached to an oscillator of piezoelectric material. This oscillator is coupled to a further oscillator thereby forming a coupled oscillator arrangement. In a most preferred embodiment, the coupled oscillator arrangement is a quartz piezoelectric tuning fork. In use, the tip piece is vibrated relative to the sample. Tip-sample interaction strains the piezoelectric material and is measurable via contacts placed on the piezoelectric material which are responsive to the strain-induced piezoelectric charge. The coupled oscillator arrangement allows a large Q of several thousand or more to be realized. The microscope is easy to operate due to the purely electrical signal collection. The probe head can operate in vacuum, at cryogenic temperatures or in high magnetic fields.