Light-emitting diode (LED) illumination for fluorescence microscopy systems has come a long way since the turn of the century, when the LED sources available had low optical power and a limited range of wavelengths. While the benefits of LED technology were attractive, their limitations prevented large-scale adoption. Twenty years later, advances in the semi-conductor industry have eliminated many of those fundamental hurdles. Today, LED technology is rapidly replacing the lamps used in microscopy and fluorescence imaging, even for applications on the extreme ends of the light microscopy spectrum. This article describes the latest advances in illumination for fluorescence imaging, from near-UV to near-IR fluorophores. Case studies demonstrate the new X-Cite® NOVEM™ as successful replacements for traditional arc lamps in calcium imaging applications, producing equivalent results with the convenience of LEDs. For its usefulness to the microscopy community, the X-Cite NOVEM system was awarded the prestigious 2021 Microscopy Today Innovation Award.
