During a materials science experiment, a laser pulse with a wavelength of λ=532 nm\lambda = 532\text{ nm}λ=532 nm in a vacuum is directed into a thin film of a newly synthesized chalcogenide glass. In this glass, the frequency of the light remains constant, but its wavelength is measured to be 37.5% of its value in a vacuum.
What is the refractive index of this chalcogenide glass?
0.380.380.38
1.601.601.60
2.672.672.67
2.752.752.75
