Refractive index basics

This page on refractive index basics covers plots of refractive index of silicon and refractive index of glass.The refractive index database link is also mentioned.

Refractive index is the ratio of velocity of light in free space to velocity of light in the medium for which it need to be calculated. The value of refractive index is always greater than or equal to one.

Refractive Index, n = c/v

The total internal reflection by Snell's Law is defined as follows:
n1*sinφ1 = n2*sinφ2
If φ2 = 90 than internal reflection takes place.
φ1 = sin-1(n2/n1)

The total internal reflection will take place if angle of incidence φ1 will be greater than or equal to critical angle φc = sin-1(n2/n1)

All the information in the optical fibre is carried using principle of total internal reflection. Moreover all the information is carried in the core part of the fibre. Cladding part does not support any transmission of information.

Refractive index database of glass and silicon

refractive index of glass refractive index of silicon

Following figures depicts refractive index of glass (optical glass type:BK7) and refractive index of silicon. As shown refractive index vary based on wavelength. Figure mentions that refractive index of glass vary between 1.56 to 1.48 based on wavelength variation. It also mentions that refractive index of silicon vary between 1.4 to 1.55.

The above refractive index database is derived from "" website. The website provides database for various glass types such as optical(BK7, BAF10, BAK1, FK51A, LASF9, SF5, SF10, SF11 etc.), multipurpose(fused silica, soda lime, schott), display glass, infrared glass, ophthalmic and more. It also mentions refractive index for other materials including SiO2, Fused silica, silicon dioxide and more.

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