Rainbow Refraction: Birefringence in IceLeah KooAward: Top 100
School: albany high school This image captures stress-induced birefringence in ice, which uses double refraction to reveal internal stress and trapped air bubbles. I placed ice over an iPad screen which emits linearly polarized backlight (light that travels in a single direction, either horizontally or vertically). The ice's hexagonal crystal structure has varying refractive indices, causing the light passing through it to undergo double refraction, splitting light into ordinary and extraordinary rays that travel at different speeds. This process rotates the light's polarization and transforms it into elliptical waves where curved air bubbles distort the path. I then took the photo with a polarizing camera lens, which acts as a selective filter for light waves based on their orientation. It blocks light traveling in the iPad screen's original polarization direction, only letting through light rotated by the ice. The resulting vibrant bands of blue, green, and pink are products of optical interference: specific wavelengths are either amplified through constructive interference when their waves line up or are canceled out through destructive interference when their waves are out of sync. These vivid interference colors highlight the ice's internal grain structures and areas of peak pressure. 
|
|