COMPARISON OF LASER AND LIGHT EMITTING DIODE ILLUMINATION FOR HIGH RESOLUTION BRIGHT-FIELD MICROSCOPY

Abstract

Medical Imagery, the most popular and challenging imagery techniques which have been a point of interest for many studies nowadays. Light microscopy requires proper illumination to acquire gigapixel high resolution and wide field of view images at the same time. Whereas incandescent light was once the only source of illumination, nowadays specialized light sources, such as laser emitting diodes (LED), lasers or arc lamps, are now being used. Light-emitting diodes (LEDs) have evolved into a serious option for practically all types of illumination in light microscopy due to their great efficiency and brightness. They are long-lasting, require no expensive electronics, and can be switched in nanoseconds. Aside from that, they have a narrow bandwidth and are available across the UV/Vis/NIR spectrum. As a result, they seem to be the most suitable illumination for different microscopy techniques. With a color temperature spanning from 2,600 to 5,000 K, the white LED is best choice for bright-field illumination, with the added benefit of being energy efficient. On the other hand, lasers produce dense packets of monochromatic light that are extremely collimated and coherent, resulting in a tight beam with a very low rate of expansion. The extremely pure wavelength ranges emitted by the laser have a

bandwidth and phase relationship that is unequalled by tungsten-halogen or arc- discharge lamps when compared to other light sources. As a result, laser light beams

can travel long distances and be expanded to span apertures or concentrated to a very small, bright spot, which reduces diffraction and maintain the light intensity. In this work we will explain in detail the differences between them using blind image quality assessments.