Physics of Light

Light as Electromagnetic Radiation

Light is a form of electromagnetic radiation that moves through space and has properties of both electric and magnetic fields (Kimura, 2020). Light has characteristics of both particles and waves (Kimura, 2020). Light travels through space similar to the way in which waves travel through the ocean. Similar to waves in the water, light has a variable wavelength; It may have large wavelengths similar to ocean waves, or it may have small wavelengths akin to the ripples seen when a pebble is dropped in a pond. The wavelength of electromagnetic radiation determines its form; X-rays have a short wavelength whilst radio-waves have a longer wavelength (Kimura, 2020). Visible light is a narrow band of electromagnetic radiation (Kimura, 2020). Within this zone, each of the colours that we can see including red, orange, yellow, green, blue, indigo and violet all represent a slightly different wavelength (Kimura, 2020). Blue has a shorter wavelength whilst red has a longer wavelength (Donnelly et al., 2025).

How Does Electromagnetic Radiation Relate to Laser safety?

In the context of laser safety, it is important to understand that lasers come in various wavelengths. This means that a laser-beam that appears red will be a different wavelength to a laser-beam that appears green. This concept is incredibly important to understand because laser safety glasses must be specifically designed to filter out the specific wavelength of the laser being used. Laser safety eyewear is not a one size fits all approach. A laser safety officer or a laser safety adviser will be able to advise what type of laser safety eyewear is required based on the laser used. Additionally, it is important to understand that if the wavelength of a laser sits out of the visible spectrum it is usually invisible; this can be incredibly dangerous primarily because we cannot spot the hazardous laser-beam. 

References

Donnelly, J., et al. (2025). Exploring light : investigations for optics education. Bellingham, Washington (1000 20th St. Bellingham WA 98225-6705 USA), SPIE.

Kimura, W. D. (2020). Electromagnetic Waves and Lasers. Bristol, Institute of Physics Publishing.