Premium
Fluorescence Microscopy Light Source Review
Author(s) -
Ladouceur AnneMarie,
Brown Claire M.
Publication year - 2021
Publication title -
current protocols
Language(s) - English
Resource type - Journals
ISSN - 2691-1299
DOI - 10.1002/cpz1.243
Subject(s) - light emitting diode , incandescent light bulb , arc lamp , optics , optoelectronics , laser , materials science , microscopy , physics
Traditional arc‐based light sources and Light Emitting Diodes (LEDs) are described, and the pros and cons of these sources with respect to fluorescence microscopy are discussed. For multi‐color applications, arc‐based light sources offer white light ranging from the ultraviolet (UV) to the infrared (IR), while LEDs come in a range of colors spanning the same wavelengths. The power of traditional arc‐based sources is controlled with neutral density (ND) filters, reducing power across the entire range of wavelengths, while LED‐based sources can be controlled directly by modulating current passing through the electronics. Similarly, arc‐based sources use physical shutters to control sample exposure to light in a range of tens to hundreds of milliseconds (ms), while LEDs can be turned ON/OFF electronically in <1 ms. The complexity of comparing and measuring light power on the sample, due to normalization of available light source spectra and complex power measurements, is discussed. The superiority of LEDs for stability of light power output is covered. Direct coupling of light sources to the microscope is more cost effective and leads to higher available light power. Various options for setting up multi‐color imaging, including high‐speed imaging with multiple LEDs and a triple cube, are described. A brief introduction to lasers, with suggested further reading, is included in this article. Finally, the smaller environmental footprint of LEDs relative to arc‐based light sources is highlighted. © 2021 Wiley Periodicals LLC. This article was corrected on 8 October 2021. See the end of the full text for details.