Apogee's newest, cutting-edge ePAR sensor was created in 2021 as an upgrade to our ePFD sensor and designed to measure the newly defined 400-750 nm ePAR radiation range that research has shown to be photosynthetically active, beyond the traditional 400-700 nm range (read article here >). Many next generation LED fixtures, the sun, and other light sources emit these newly confirmed Far-red photosynthetic wavelengths, but they have not been measurable by traditional 400-700 nm PAR meters until now. Much of the transformative work to define the ePAR range was conducted by Dr. Shuyang Zhen and Dr. Bruce Bugbee at Utah State University's Crop Physiology Laboratory. The most recent article by Dr. Zhen and Dr. Bugbee can be found in the New Phytologist. A few of the many articles by these researchers discussing ePAR can be found in Greenhouse Management, Plant, Cell and Environment, Frontiers in Plant Science, and at Fluence.