In optics, the corpuscular theory of light, apparently put forth by Descartes in 1637, states that light is comprised of little discrete particles called “corpuscles” (little particles) which travel in an orderly straight line fashion with a limited speed and have driving kinetic force. This depended on a substitute portrayal of atomism of the time-frame.

Isaac Newton was a pioneer of this hypothesis; he remarkably expounded upon it in 1672. This early origination of the particle hypothesis of light was an early harbinger to the advanced modern comprehension of the photon. This theory can’t clarify refraction, diffraction and obstruction interference, which require a comprehension of the wave hypothesis of light of Christiaan Huygens.

How was Corpuscular theory wrong?

The corpuscular theory was to a great extent created by Isaac Newton. Newton’s hypothesis was predominant for over 100 years and overshadowed Huygens’ wave hypothesis of light, mostly as a result of Newton’s extraordinary prestige. When the corpuscular hypothesis neglected to satisfactorily clarify the diffraction, interference and polarization of light it was deserted for Huygens’ wave hypothesis. Somewhat, Newton’s corpuscular particle hypothesis of light reappeared in the twentieth century, as a light phenomenon is as of now clarified as particle and wave.

It couldn’t clarify wonder like interference, diffraction, polarization and so forth This hypothesis anticipated that speed of light in a denser medium is more than the speed of light in a rarer medium which was tentatively refuted by Foucault (person). Thus Newton’s corpuscular hypothesis was rejected.

Now what is Polarization & Diffraction?

Diffraction, interference, and polarisation can be understood in terms of the wave properties of light. All waves diffract and interfere — you can see this just as easily with water waves, sound waves in air, earthquake tremors and so on, as well as light. Ripple tanks are often used to demonstrate wave phenomena in water.

Diffraction is the tendency of a wave to spread out around obstructions. It’s why you can hear sounds even if there’s, say, a building between you and the sound source. You can see diffraction most clearly when a wave is passed through a small slit, comparable in width to the the wavelength:

Diffraction is often described in terms of the Hugens, or Huygens-Fresnal principle, whereby each point on the wavefront of a wave can act as a point source for further wave propagation. The modern explanation for light is different, but the end result is the same.

Interference is where two waves overlap and peaks and troughs either reinforce each other or cancel out often producing interference fringes. You can see both phenomena together here where a slightly wider slit produces diffracted waves from each edge of the slit, and these two waves subsequently interfere:

Polarisation is the direction of orientation of a transverse wave as it propagates. It’s also possible to have circular polarisation of a light wave where the wave precesses as it travels:

How to Understand Light correctly?

Light, or Visible Light, commonly refers to electromagnetic radiation that can be detected by the human eye. The entire electromagnetic spectrum is extremely broad, ranging from low energy radio waves with wavelengths that are measured in meters, to high energy gamma rays with wavelengths that are less than 1 x 10^-11 meters. Electromagnetic radiation, as the name suggests, describes fluctuations of electric and magnetic fields, transporting energy at the Speed of Light (which is ~ 300,000 km/sec through a vacuum). Light can also be described in terms of a stream of photons, massless packets of energy, each travelling with wavelike properties at the speed of light. A photon is the smallest quantity (quantum) of energy which can be transported, and it was the realization that light travelled in discrete quanta that was the origins of Quantum Theory.

Figure 1: The Electromagnetic Spectrum, highlighting the narrow window of Visible Light that is detectable by the human eye.

Visible light is not inherently different from the other parts of the electromagnetic spectrum, with the exception that the human eye can detect visible waves. This in fact corresponds to only a very narrow window of the electromagnetic spectrum, ranging from about 400nm for violet light through to 700nm for red light. Radiation lower than 400nm is referred to as Ultra-Violet (UV) and radiation longer than 700nm is referred to as Infra-Red (IR), neither of which can be detected by the human eye. However, advanced scientific detectors, such as those manufactured by Andor, can be used to detect and measure photons across a much broader range of the electromagnetic spectrum, and also down to much lower quantities of photons (i.e. much weaker light levels) than the eye can detect.

References:

Wikipedia, Oxford Instruments & Blog from Boutros Gladius, Astrophysicist via Quora.