Optics question-vacuum chamber for Ellipsometry

In summary, the conversation is about building a cover/chamber for a sample in an ellipsometry setup. The chamber needs to enclose the sample in a vacuum or inert gas environment and have two windows for light to pass through. Visible light is used and measurements are taken at a fixed angle of 65 degrees. The speaker is seeking expert advice on factors to consider, such as polarization change, refractive index, and transmittance, in designing the chamber. They also provide a picture of the current setup for reference.
  • #1
ecnerwalc3321
8
0
I have shown a picture of our current ellipsometry setup. The sample is placed in the center. Polarized light comes in from the left barrel, reflects off the sample, and enters the barrel on the right. What I'm looking to build is a cover/chamber this that covers the sample but does not affect measurements to a great extent. The chamber is to enclose the sample in either a vacuum or inert gas environment. Obviously, two windows on the chamber have to be made in order for light to pass through and hit the sample. Visible light is used; normally we analyze data from 400nm upwards. Measurements are taken at a fixed angle (as shown in picture, 65 degrees).

I was hoping to double check my reason with some experts here before having this thing retrofitted. I do not deal with optics at all; after plowing through many textbooks and seeing how fertile the field is, I'm afraid that I'll overlook some physical phenomenon in designing this thing.

I feel that the factors that I need to be concerned about include polarization change as light passes through windows, refractive index, and transmittance. Is there anything else that needs to be considered? Is this problem as simple as building a chamber that has two windows at 65 degrees (normal to incident light to minimize refracted light) with a material that is offers close to 100% transmittance in the wavelength that I want?

Thank you very much for your input.
 
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  • #2
Below is the picture I promised.
 

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1. What is a vacuum chamber?

A vacuum chamber is a device used to create and maintain a controlled environment with low atmospheric pressure, typically lower than what is found at sea level. This is achieved by removing air and other gases from the chamber, creating a vacuum.

2. Why is a vacuum chamber necessary for Ellipsometry?

A vacuum chamber is necessary for Ellipsometry because it eliminates the interference of ambient air and gas molecules, which can affect the accuracy of the measurements. In a vacuum, the sample can be analyzed under ideal conditions, allowing for more precise results.

3. How does a vacuum chamber affect the measurements in Ellipsometry?

A vacuum chamber affects the measurements in Ellipsometry by creating a more stable and controlled environment for the sample. This reduces the impact of environmental factors, such as temperature and humidity, on the measurements and improves the accuracy and repeatability of the results.

4. What are the key components of a vacuum chamber for Ellipsometry?

The key components of a vacuum chamber for Ellipsometry include a vacuum pump, which removes air and gases from the chamber, a pressure gauge to monitor the pressure inside the chamber, and a sample stage where the sample is placed for analysis. Other components may include valves, filters, and seals to maintain the vacuum and control the flow of gases in and out of the chamber.

5. Are there different types of vacuum chambers for Ellipsometry?

Yes, there are different types of vacuum chambers for Ellipsometry, such as batch chambers, where multiple samples can be analyzed at once, and single-sample chambers, which are designed for analyzing one sample at a time. There are also different sizes and shapes of vacuum chambers to accommodate various sample sizes and shapes.

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