# Thread: The laser used in cornea

1. ## The laser used in cornea

The laser used in cornea surgery to treat corneal disease is the excimer laser, which emits ultraviolet light with a wavelength of 193 nm in air. The index of refraction of the cornea is 1.376. What are the wavelength and frequency of the light in the cornea?

2. Originally Posted by tacubo
The laser used in cornea surgery to treat corneal disease is the excimer laser, which emits ultraviolet light with a wavelength of 193 nm in air. The index of refraction of the cornea is 1.376. What are the wavelength and frequency of the light in the cornea?
The frequency is the same in both media, then as:

$\displaystyle \lambda=\frac{c}{f}$

the wavelength is proportional to the speed of light, and the refractive index
$\displaystyle n$ is the ratio of the seed of light in vacuum to that in the medium, so we have:

$\displaystyle \frac{\lambda_1}{\lambda_0}=\frac{c_0}{c_1}=n$.

where $\displaystyle \lambda_0$ is the wavelength in vacuum (virtually the
same as in air). So:

$\displaystyle \lambda_1=n \lambda_0$,

and as you are told $\displaystyle n$, and $\displaystyle \lambda_0$, you can complete the answer.

RonL