What type of source is used in young's double slit experiment?

What is Young's Double Slit Experiment?

In the fascinating world of quantum mechanics, there are experiments that challenge our understanding of reality, leading us down the rabbit hole of uncertainty and wonder. One such experiment, Young's Double Slit Experiment, is a cornerstone in the realm of quantum physics, shedding light on the wave-particle duality of matter and the strange behaviour of light  and What Type of Source is used in Young's Double Slit Experiment?.
 
Figure 1 shows schematically the experimental set up. Vertical narrow slits S1, and S2 are cut in an opaque plate. A monochromatic, parallel beam of light is allowed to fall on the slits. The light going through the two slits is collected on a screen placed on the other side of the slits. It is found that the intensity of light on the screen varies alternately between a maximum and a minimum value. If the two slits are identical, the minimum intensity is zero. What we visually se are bands of high and low intensities called bright and dark fringes. 
 
We can put a photographic plate in place of the screen and perform the experiment in a dark room, carefully avoiding stray lights. The film may later be developed to have a permanent record of bright and dark bands formed. Else, you can put up a photo sensitive screen and the intensity pattern can be stored in a computer system.

source:wikipedia

Understanding the Experiment:

Imagine a dark room with a screen at one end, and in the centre of that screen, there's a small opening, or slit. Behind this screen, there's a source of light, emitting waves that pass through this single slit, creating a pattern of light on the screen. So far, so good, right? But here's where it gets interesting.

Now, instead of one slit, we introduce another slit right next to the first one. This means there are now two openings for light to pass through. What do you think will happen? Well, classical physics might lead us to believe that we'd simply see two bright spots of light on the screen, aligned with the slits. But that's not what happens.

When both slits are open, something peculiar occurs. Instead of just two bright spots, we observe a pattern of alternating bright and dark bands on the screen. This pattern is known as an interference pattern, and it's a key feature of wave behaviour.

To comprehend why this interference pattern forms, we need to consider the wave nature of light. Light behaves as a wave, with crests and troughs that can interfere constructively (creating brighter areas) or destructively (creating darker areas) when they overlap.

When light passes through the two slits, it behaves like waves emanating from each slit, creating a series of overlapping wavefronts. Where the crests of one wave align with the crests of another, they reinforce each other, resulting in brighter regions on the screen (constructive interference). Conversely, where a crest aligns with a trough, they cancel each other out, leading to darker regions (destructive interference).

What Type of Source is used in Young's Double Slit Experiment?

In Young's Double Slit Experiment, the source of light can vary. Originally performed with sunlight or candlelight, modern versions often use lasers or monochromatic sources, which emit light of a single wavelength. This choice ensures that the interference pattern is clear and distinct, making it easier to observe and analyse.

The significance of Young's Double Slit Experiment:

Young's experiment is more than just a demonstration of wave behaviour; it's a profound illustration of the wave-particle duality of light. It shows that light exhibits properties of both waves and particles, depending on how it's observed or measured.

Closing Thoughts:

Young's Double Slit Experiment continues to captivate scientists and enthusiasts alike, inviting us to ponder the fundamental nature of reality. It challenges our preconceptions and beckons us to explore the mysterious realm where particles behave like waves and the very fabric of the universe seems woven from uncertainty. So the next time you find yourself in a dark room, contemplating the nature of light, remember Youngs double slit experiment and marvel at the beauty of quantum mechanics.