How does coherent light affect single-slit diffraction results?

Coherent light in single-slit diffraction results in a clear and well-defined diffraction pattern.

In single-slit diffraction, light waves pass through a narrow slit and spread out, creating an interference pattern on a screen. This pattern is characterised by a central bright fringe (maximum) surrounded by alternating dark and bright fringes (minima and maxima). The clarity and definition of this pattern are significantly influenced by the coherence of the light source used.

Coherent light is light in which the waves are all in phase with each other, meaning they have the same frequency and wavelength and the phase difference between them remains constant over time. Examples of coherent light sources include lasers and monochromatic light. When coherent light is used in single-slit diffraction, it results in a well-defined and clear diffraction pattern. This is because the waves interfere constructively and destructively in a predictable and consistent manner, creating distinct bright and dark fringes.

In contrast, if the light source is not coherent, the resulting diffraction pattern may be blurry or less distinct. This is because the waves are not in phase with each other and the phase difference does not remain constant over time. As a result, the waves interfere in a less predictable and consistent manner, leading to a less clear interference pattern.

Furthermore, the use of coherent light in single-slit diffraction allows for more precise measurements and calculations. The position and intensity of the fringes in the diffraction pattern can be used to calculate the width of the slit, the wavelength of the light, and other properties. The accuracy of these calculations depends on the clarity and definition of the diffraction pattern, which in turn depends on the coherence of the light source.

In summary, coherent light plays a crucial role in single-slit diffraction, affecting the clarity and definition of the resulting diffraction pattern and the accuracy of measurements and calculations based on this pattern.