Piezo Crystalline Phase Shifter with Picoactuator® Technology: Precision Without Position Sensor

Phase shifters are used in laser measurement to align optical path lengths. These move optics in the range of a wavelength, which corresponds to an adjustment range of less than one micrometer. It is crucial for the alignment to take place quickly and in a stable manner.

For the new S-303.BL phase shifter, PI (Physik Instrumente) replaces classic piezo ceramic PZT actuators (made of lead titanate – lead zirconate) with pico actuators made of a crystalline, lead-free material. These pico actuators are characterized by a particularly high linearity, so that precision positioning is also possible in open-loop operation. With a travel range of 0.3 micrometers, they achieve a precision of 6 nanometers, which corresponds to a linearity of 2%.

In comparison to classic piezo ceramics, however, pico actuators have a smaller displacement. Ideal fields of application are therefore wherever high dynamics, short travel ranges and high precision requirements are necessary.

Open-loop operation does without the use of a position sensor in favour of the system bandwidth and costs. This simplifies the mechanical structure and the electronic control; servo cycle delays do not occur. The S-303.BL is thus a precise yet dynamic drive for optics in the range of a wavelength.

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