Linear Piezo Motor for Highly Precise Laser (Grating) and Spectrophotometer Tuning

Piezo stacks and piezo chip actuators have long been used for optical cavity tuning. Together with capacitive sensors very precise Fabry Perot filters can be designed.   While displacement ranges of traditional piezo stacks are typically limited to the 10’s of micron ranges,  piezoelectric motors provide longer ranges.

Many of today's tunable lasers rely on the performance of a micropositioning or nanopositioning actuator to position a diffraction grating with extreme precision and repeatability. While the virtually unlimited resolution and extremely fast response of piezo stack actuators is very desirable in these applications, their limited travel (typically <100 µm) is often a K.O. criterion. To overcome the limited range, DC-motorized micrometers and stepper-motor-driven leadscrew actuators have been employed by laser manufacturers in the past.

However, these systems cannot provide the ultra-smooth piezo-class motion required for wavelength sweeps. Their precision is also affected by friction and backlash of the mechanical drive screw and their limited dynamic performance leaves laser designers wanting.

A novel, ultra-compact linear drive based on the PiezoWalk® principle has been developed by PI to overcome the limitations of conventional linear actuators. The precision actuator, dubbed NEXACT®, combines virtually unlimited travel ranges with high stiffness and bandwidth in a very small package. Furthermore, NEXACT® actuators provide piezo-class resolution (far below one nanometer) and millisecond response. The special drive design works with a very low operating voltage of 40 V and below.

The NEXACT® drive is the ideal precision linear actuator for OEMs. It provides extremely high dynamics, resolution and stability. Its miniature size (only 25x25x12 mm) along with easy control and long lifetime (no wear) allow seamless integration into the final product.