Systems and Control > Optical measurements and laser instrumentation


Research in Optoelectronic Measurements and Sensors concerns several aspects related to methodology and proposal of novel measurement architectures, development of innovative optical sensors, experimental characterization of devices and systems. In particular, new self mixing interferometric measurement systems are being studied and developed and tested. A second major research project pursued by the Group is the theoretical and experimental analysis of a novel high resolution and high accuracy optical Time Of Flight telemeter.

Fig. 1. Laser self-mixing vibrometer
Fig. 2. External-Cavity Laser Diode for high-resolution spectroscopy
Fig. 3. Optical sensor to measure turbine radial dimensions

Copyright © Ing. Giorgio Uccellini 2009

Most relevant research achievements

Laser self-mixing measurement systems
Optical interferometric measurement systems based on self mixing technique, internal to a semiconductor laser diode, are being issued to develop compact and simple but at the same time accurate vibrometers, absolute telemeters, and flowmeters. The developed vibrometer reaches a noise equivalent displacement as low as 50 pm/root(Hz) and can measure directly on human skin for biomedical porpouses; the flowmeter is included in an optical probe for extracorporeal blood flow measurement, with resolution better than 0.1 l/min for flow rates up to 6 l/min.

Hi-res and high-accuracy optical Time Of Flight (TOF) telemeter
A novel detection scheme for a pulsed TOF laser telemeter was studied and experimentally implemented. The optical pulses of a mode locked fiber laser, at 250 MHz repetition rate, are detected via an heterodyne technique. The phase lag analysis, carried on the down converted electrical signal, allowed to equivalently resolve few femtosecond time intervals and hence a 10 µm distance resolution. Absolute calibration of the new telemeter was carried at the National Metrological Institute of Italy (INRiM).