The ability to see an object is directly related to the wavelength of the light used to observe it. When the size of an object is smaller than the wavelength of the light, a phenomenon known as diffraction occurs, which affects the propagation and interaction of light waves.
Diffraction refers to the bending or spreading of light waves as they encounter an obstacle or pass through a narrow opening. This phenomenon is a characteristic property of waves, including electromagnetic waves such as light. The degree of diffraction is influenced by the ratio of the size of the obstacle or opening to the wavelength of the incident light.
When the size of the object is comparable to or smaller than the wavelength of the light, the diffracted light waves spread out significantly, resulting in a blurred or distorted image. This effect is known as the diffraction limit or the Rayleigh criterion, and it sets a fundamental limit on the resolution or level of detail that can be observed with a particular optical system.
To overcome the limitations imposed by diffraction, scientists and engineers use various techniques. One such approach is to use shorter-wavelength light sources, such as electron beams in electron microscopes, to achieve higher resolution imaging. Another technique is to use specialized optical systems, such as those based on super-resolution microscopy, which can bypass the diffraction limit by employing clever computational algorithms and physical tricks.
It's important to note that the inability to see objects smaller than the wavelength of light is not solely due to diffraction. There are other factors that can affect visibility, such as the intensity of the light, the properties of the object (such as its reflectivity or transparency), and the detection capabilities of the imaging system being used.
In summary, objects smaller than the wavelength of light cannot be seen clearly because diffraction causes the light waves to spread out, resulting in a loss of resolution and a blurred image. Overcoming this limitation requires the use of techniques that exploit shorter wavelengths or employ advanced imaging methods to achieve higher resolution.