Compare absorption spectra from calculation and experiment

In summary: Overall, it is important to carefully consider the incident angle when conducting optical simulations and experiments for accurate absorption spectrum measurements. In summary, when performing absorption spectrum measurements on nanoscale substrates, the incident angle of the white light should be kept as close to normal as possible for accurate results.
  • #1
lhk
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hi pf nice to see you. I have a question about optical absorption spectrum of nanoscale substrates. To get an absorption spectrum of nanostrucutred material, I want to perform both fdtd calculation and optical simulation. When I do fdtd calculation, I set the incident light illuminated with normal incidence as I believe other researchers have same incident condition and I have a result. The result seems to make sense and is as I expected so I want to move on to the real experiment. To measure the absorption spectrum, my setup is simply to normalize the intensity of the transmitted or reflected light through or from my sample with the intensity of referenced white light. The white light goes through the objective lens and in the case of transmission spectrum the transmitted light is collected by another objective lens. My question here is: when the white light illuminated the sample how the incident angle matters? Actually I am not sure how I can say about the incident angle with white light source. I see many previous researches but it seems that they do not much care about the incident angle of white light. Thank you for time and if you have any comments please share yours.
 
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Thank you for your question! The incident angle of white light does matter when taking an absorption spectrum. In general, the incident angle of the white light should be kept as close to normal as possible in order to maximize the accuracy of the measurement. If the angle is too large, this can lead to refraction effects which can affect the accuracy of the measurements. Additionally, the objective lenses used for collecting the transmitted light should also be adjusted to account for the incident angle of the white light. It is important to note that the incident angle of the white light may need to be adjusted depending on the sample size and geometry.
 

Related to Compare absorption spectra from calculation and experiment

1. What is an absorption spectrum?

An absorption spectrum is a graphical representation of the amount of light absorbed by a substance at different wavelengths. It is often used to identify the chemical composition of a substance by comparing it to known spectra.

2. How are absorption spectra calculated?

Absorption spectra can be calculated using theoretical models and equations, such as the Beer-Lambert Law, which relates the amount of light absorbed to the concentration of a substance and the path length the light travels through the substance.

3. What is the difference between calculated and experimental absorption spectra?

Calculated absorption spectra are based on theoretical models and equations, while experimental absorption spectra are obtained through actual measurements in a laboratory setting. There may be slight variations between the two due to experimental error or limitations of the theoretical model.

4. Why is it important to compare absorption spectra from calculation and experiment?

Comparing absorption spectra from calculation and experiment can help validate the accuracy of the theoretical models and equations used to calculate the spectra. It can also provide insights into the chemical properties of a substance and help identify any discrepancies or errors in the experimental data.

5. Can absorption spectra be used to determine the purity of a substance?

Yes, absorption spectra can be used to determine the purity of a substance by comparing the experimental spectra to the spectra of known pure substances. If the experimental spectra match the pure spectra, then the substance is likely pure. Any deviations or additional peaks in the experimental spectra may indicate impurities in the substance.

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