Picoscale sensing with telecom parts
2012 R&D 100 Winner
In order to linearize the scan generation of its scanning probe microscopes, attocube systems AG, Munich, Germany, required a low-temperature compatible optical displacement sensor.
The result is the FPS3010 - Real Time Interferometric Sensor, a high-bandwidth optical displacement sensor with sub-meter range and the ability to read target position variations at the picometer level. High sensitivity is achieved by two subsystems.
The first is a multitude of compact, passive-displacement sensing heads connected by standard telecom optical fibers. Each sensing head is built from a single-mode fiber; a miniature collimating lens is integrated into the fiber to achieve millimeter-scale sensor dimensions. The second subsystem is formed by a central laser diode and an electronic control unit, to which each sensor head is connected by its own single-mode fiber. The electro-optic controller remotely supplies each sensor head with laser power, collecting the interferometric position signal through the same telecom fiber. A quadrature signal of the interferometric beats is generated using a patented technique allowing the measurement of both the displacement and its direction. The use of telecom laser wavelengths—which are temperature controlled and locked to a NIST-traceable gas cell to ensure accuracy—allows for operation with large distances between the sensor head and the control unit.
Laser-powered optical displacement sensor
attocube systems AG
The FPS3010 – Real Time Interferometric Sensor Development Team from attocube systems AG
Martin Zech, Principal Developer