Sub-micron positioner with optical determination of location comprises first and second modules moved relatively, with laser source, optical modulator and optical fiber connections

摘要

First and second modules (1, 4) can be moved relatively. An intermediate relative position adjuster (2, 3) produces the movement. The location of an optical modulator (50) is determined by the position of the second module (4). An optical waveguide (53) transmits light illuminating the modulator (50). This is external to the positioner and coupled mechanically with the first module (1). Light so modulated is taken from the positioner by the first optical waveguide (53) or by a second optical waveguide brought to the positioner from outside. Adjustment is provided by an actuator exploiting a slip-stick mechanism. It includes one or more piezoelectric components. The optical modulator is an optical grating. The complete system also includes a light source (54) for illumination, and a detector (55, 56) for the modulated returns, converting them into an electrical signal. The modulated light is transmitted away from the positioner by the first optical waveguide (53) connected to a beam splitter (57). This is connected to the source and detector by further optical waveguides. The positioner is accommodated in a sealed enclosure (58), the optical waveguides being passed through wall penetrations. The enclosure is a low-temperature cryostat in which there is a large magnetic field and an ultra-high vacuum.