A silicon wafer is used to attenuate the intensity from a laser emitting at a wavelength of 0.8 µm. If the laser output power is 100 mW what is the wafer thickness required to attenuate the power to 1 mW?

Respuesta :

Answer:

[tex]t =4.605 *10^{-3}[/tex]

Explanation:

given data:

wavelength of emission =[tex]0.8 \mu m[/tex]

output power = 100 mW

We can deduce value of obsorption coefficient from the graph obsorption coefficient vs wavelength

for wavelength [tex]0.8 \mu m[/tex] the obsorption coefficient value is 10^{3}

intensity can be expressed as a function of thickness as following:

[tex]I(t) = I_{O} *e^{-\lambda *t}[/tex]

putting all value to get thickness

[tex]1*10^{-3} =100*10^{-3}e^{-10^{3}*t}[/tex]

[tex]0.01 = e^{10^{3}t}[/tex]

[tex]t =4.605 *10^{-3}[/tex]