Building a Laser - Brewster's Angle Problem

In summary, the conversation discusses the process of making a laser with a MgF2 window and external mirrors. It is mentioned that the end of the gas discharge tube must be cut at Brewster's angle to avoid reflection from the surface. The solution is to calculate the Brewster's angle, which is found to be 53.952 degrees, and also state how the window should be oriented for polarization in the vertical plane. The window orientation can be found in the Wikipedia article on Brewster angle.
  • #1
VitaX
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Homework Statement



You are making a laser with light of wavelength 310 nanometers using a MgF2 window (which will transmit the UV). The mirrors will be external so each end of the 'pumping' gas discharge tube must be cut at Brewster's angle so that there is no reflection from the surface as the light passes through it. Calculate the proper angle and state how to orient the part so that the output is polarized in the vertical plane.

Homework Equations



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The Attempt at a Solution



θB = arctan(1.374) = 53.952 degrees

Is this really all this problem is? Just finding the Brewster's angle, and that's the answer? Or is there something more complex that I'm missing here?
 
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  • #2
You also have to say how the window is oriented.
The Wikipedia article on Brewster angle shows this.
 

What is Brewster's Angle and why is it important in building a laser?

Brewster's Angle is the angle at which light is completely polarized when it reflects off a medium with a higher refractive index. In laser building, this angle is important because it allows for maximum reflection and reduces the amount of energy lost through refraction.

How do you calculate Brewster's Angle?

Brewster's Angle can be calculated using the formula: θ = arctan(n2/n1), where n2 is the refractive index of the medium the light is reflecting off of and n1 is the refractive index of the medium the light is traveling through.

What are the potential challenges in achieving Brewster's Angle in laser building?

One challenge is finding a material with the right refractive index to achieve Brewster's Angle. Additionally, the laser beam must be precisely aligned to hit the surface at the correct angle. Any imperfections in the material or the alignment can result in losses in energy and a less efficient laser.

How does Brewster's Angle affect the polarization of light in a laser?

At Brewster's Angle, the reflected light is completely polarized, meaning that the electric field oscillates in only one plane. This allows for a more coherent and focused laser beam.

Are there any alternative methods for achieving polarization in laser building?

Yes, there are other methods for achieving polarization in laser building, such as using polarizing filters or incorporating a polarizing element into the laser cavity. However, Brewster's Angle is often preferred as it allows for maximum reflection and minimal energy loss.

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