Why do shorter wavelengths provide better resolution?

Shorter wavelengths provide better resolution because they can detect smaller details that longer wavelengths cannot.

In physics, the concept of resolution is closely tied to the wavelength of the wave being used. The resolution of an imaging system, such as a microscope or telescope, is essentially its ability to distinguish between two points or objects that are very close together. The shorter the wavelength of the light (or other form of electromagnetic radiation) being used, the better the resolution.

This is because when light interacts with an object, it can either be absorbed, reflected, refracted, or diffracted. Diffraction is the bending of light around the corners of an obstacle or aperture. The amount of diffraction that occurs is directly proportional to the wavelength of the light. Therefore, shorter wavelengths will diffract less and can more accurately pinpoint the location of an object, leading to a higher resolution image. For a more detailed understanding, you might find the page on diffraction patterns helpful.

The principle of diffraction limits the resolution of an imaging system. This is known as the diffraction limit. The diffraction limit is given by the formula: Resolution = 1.22 * (wavelength / aperture diameter). From this formula, it is clear that as the wavelength decreases, the resolution improves. The concept of limitations of resolution due to diffraction is crucial in understanding this principle in depth.

This principle is utilised in various scientific and technological applications. For example, electron microscopes use electrons (which have much shorter wavelengths than visible light) to achieve much higher resolution than optical microscopes. Similarly, in telecommunications, higher frequency (and therefore shorter wavelength) signals can carry more information, improving the resolution of the transmitted data.

IB Physics Tutor Summary: Shorter wavelengths provide better resolution in imaging systems like microscopes and telescopes because they diffract less around objects. This reduced diffraction enables a clearer distinction between closely positioned points, enhancing the image's detail. Essentially, using shorter wavelengths allows for more precise visualisation of small details, improving the overall image clarity.