Thin film interference is an important content in the teaching of wave optics
in University Physics，
and it is also the theoretical basis of thin film optics. One of the most
important applications of thin film interference
is to design antireflection and high reflection coatings. Reflectance of
multilayer dielectric film is quantitatively calculated
based on transfer matrix method in the manuscript. The reflectance of the
one BK7 glass surface without
coatings is about 4% over the visible spectrum; Low reflectance can be
obtained by destructive interference of the
thin film. The reflectance of single antireflection coating on glass
decreases to 1.3% at the designed wavelength，
550nm. However，performance of such quarter-wave coatings falls off when
deviating from the designed wavelength.
The reflectance of double antireflection coatings on glass maintains low
reflectance，less than 1.3%，over the 470～
670 nm wavelength range. On the contrary，high reflectance can be obtained
by constructive interference of the thin
film. The reflectance of fused quartz can be increased from 3.3% for the
bare surface to 30% for the single layer
high reflection coating at the designed wavelength，1500nm. The reflectance
of the seven groups of films can reach
more than 99% over the 1360 ～ 1660 nm wavelength range. Through these
quantitative calculations，students can
have a deeper understanding of the application of theoretical knowledge in
practice，cultivate their engineering
awareness and enhance their interest in learning.
Just Accepted
