High-resolution, very broadband force measurements by solid-state laser transducers

Novel high-performance force transducers are discussed. Force measurement is based on the photoelastic effect in solid-state lasers (diode-pumped Nd:YAG) and provides an electrical frequency output. Our experiments demonstrate that the dynamic range of a single monolithic laser transducer covers at least 9 decades in which the output frequency is strictly proportional to the input force magnitude. Within the measurement bandwidth from DC up to at least 100 kHz force modulation frequency, static sensitivity of the transducer equals its dynamic sensitivity. Furthermore, input signals with modulation frequencies up to the MHz range can also be detected. The total measurement range covered by the applied laser technology ranges from nano-newton to mega-newton depending on the size of the laser crystals.