Editing Sample Thickness Measurement via Multi-wavelength Laser Interferometry (section)

===Data Preprocessing===

Because laser interferometric measurement is essentially a comparative measurement that uses the wavelength of light as a ruler, even slight fluctuations in the refractive index of air will directly introduce systematic errors. This experiment was carried out under strictly controlled laboratory conditions, and the air parameters at the time of measurement were recorded in real time using an environmental monitor: ambient temperature 21.90°C ± 0.05°C, pressure 1009 hPa, and relative humidity 55%. According to the Edlén correction formula described above, these environmental parameters were substituted into the calculation, yielding the corrected refractive indices: <math>n_1 = 1.000268687558227179</math> for red light, <math>n_2 = 1.000269432843863667</math> for yellow light, and <math>n_3 = 1.000274643309471638</math> for violet light. The corresponding wavelengths in air were then obtained as <math>0.6498254\ \mu\text{m}</math> for red light, <math>0.5938400\ \mu\text{m}</math> for yellow light, and <math>0.4048888\ \mu\text{m}</math> for violet light.

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The thickness of the sample, as measured with a vernier caliper, was between <math>1.98</math> and <math>2.02\ \text{mm}</math>.

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