Why Is Huygens Construction Not Used for Double Slit Diffraction?

[SimonB]

A conceptual problem for me anyway!

In the standard texts a Huygens construction is used to explain the diffraction pattern from a single slit. However it is not used in the explanations for double (or multiple slits). What is the justification for this ... the double slit pattern should be two single slit patterns interfering but is that just over complicating things?

Thanks in advance

Simon

 

[SimonB]

I think I have now answered this (?) :

http://www.physics.rutgers.edu/ugrad/labs/1lw.html

 

[astrokreng]

Hello Simon,

Thank you for bringing up this interesting question about Huygens and diffraction. The Huygens construction is a theoretical model that explains the behavior of light as it passes through a single slit. It is based on the principle that every point on a wavefront can be considered as a source of secondary spherical waves, and the interference of these waves creates the diffraction pattern.

However, when it comes to double or multiple slits, the Huygens construction becomes more complex and does not fully explain the observed diffraction pattern. This is because the interference of multiple waves from different sources creates a more intricate pattern, and the Huygens construction does not fully account for this.

Instead, the diffraction pattern from double or multiple slits is better explained using the concept of superposition, where the amplitude of each wave is added together to create the overall pattern. This approach is simpler and more accurate in explaining the diffraction pattern from multiple slits.

In summary, while the Huygens construction is a useful tool for understanding diffraction from a single slit, it becomes more complicated and less accurate when applied to multiple slits. Therefore, the use of superposition is a more appropriate approach for explaining the diffraction pattern in these cases.

I hope this helps clarify your conceptual problem. Keep exploring and questioning, as that is the essence of science!