Polytec offers laser Doppler vibrometer for characterising the dynamic behaviour of MEMS
Laser Doppler vibrometer
Polytec has introduced the UHF-120 laser Doppler vibrometer (LDV), which, featuring a frequency range of up to 1,200MHz, is designed for the characterisation of high-frequency dynamic behaviour of micro components and HF transducers.
According to the company, the laser Doppler vibrometer enables engineers to investigate the dynamics of micro components such as MEMS, transducer technologies and combinations of micro- and nanotechnology with ultrasonic actuation, characterising mechanical responses at these frequencies and displacements.
It suits such tasks because laser-based, non-contact optical testing avoids mass loading from direct contact to provide the entire frequency range split into phases, as well as allowing analysis of transients and decay phases in the time domain.
Polytec’s UHF-120 ‘ultra-high-frequency’ vibrometer has an extended bandwidth that allows characterisation of out-of-plane vibration frequencies bandwidth up to 1.2GHz and the velocity range to more than 100m/s.
The J12 series of indium arsenide (InAs) detectors from Pacer are photovoltaic infrared photodiodes sensitive in the 1.0µm to 3.8µm wavelength region.
As Linear Technology’s Jim Williams explains, a large group of fibre-optic lasers are powered by DC current. Laser drive is supplied by a current source with modulation added further along the signal path. The current source, although conceptually simple, constitutes a tricky design problem. There are a number of practical requirements for a fibre-optic current source and failure to consider them can cause laser and/or optical component destruction.
Sensl’s B-series of fast, blue-sensitive silicon photomultiplier sensors, available from AP Technologies, is designed for ultra-fast timing applications.
Continued demands for increased bandwidth have resulted in deployment of fibre-optic-based networks. This application note discusses ‘climactic pampering for temperamental lasers’.
The document describes an isolated high-power-factor TRIAC-dimmable LED driver designed to drive a nominal LED string voltage of 34V at 370mA.