licor par
source : LI-COR website

The PAR quantum sensors measure PAR in units of photosynthetic photon flux density (PPFD). They are photovoltaic sensors with hemispherical field of view achieved by a diffuser. Filters are used to allow radiation between 400 to 700nm to pass through. Several commercial PAR sensors are available such as: LI-190R Quantum SensorMQ-303, Quantum sensors by apogee instruments.