polarisation

Question 1

polarisation by reflection

Answer 1

• unpolarised light will resolve into two perpendicular components when incident on a flat surface
• when the reflected wave is perpendicular to the refracted wave, light that is specularly reflected is place-polarised in the plane of surface
• incident angle that cause plane-polarisation is referred to as Brewster’s angle

Question 2

polarisation by transmission

Answer 2

• Results from having conducting material consisting of fine grid arranged either vertically or horizontally
• Light traveling parallel to the absorption axis is absorbed. Light travelling parallel to the transmission axis is transmitted as polarised light
• Polaroid sunglasses with vertical transmission axis does not transmit horizontally plane polarised light reflected at Brewster’s angle from flat horizontal surfaces

Question 3

polarisation by refraction

Answer 3

• Occurs when light passes through an anisotropic material
• Results in different refractive index and absorption strength in different directions
• Different polarisation component travels at different speed
• Results in two rays and forms two images

Question 4

polarisation by scattering

Answer 4

• Occurs when light hits any material (non-homogenous) and scatters
• It results scattered light to become either completely or partially polarised
• Scattered light perpendicular to the incident light is completely polarised
• As angle varies, polarisation decreases