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Airy Disk Formula:
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The Airy disk formula calculates the resolution limit of a microscope based on the wavelength of light used and the numerical aperture of the objective lens. It determines the smallest distance between two points that can still be distinguished as separate entities.
The calculator uses the Airy disk formula:
Where:
Explanation: The formula shows that resolution improves (smaller value) with shorter wavelengths and higher numerical apertures.
Details: Resolution is a fundamental parameter in microscopy that determines the level of detail visible. Understanding the theoretical resolution limit helps in selecting appropriate equipment and interpreting microscopic images.
Tips: Enter the wavelength of light in μm (e.g., 0.55 μm for green light) and the numerical aperture of your objective lens (typically 0.1 to 1.4 for air and oil immersion objectives).
Q1: What is the 1.22 factor in the formula?
A: This is the first zero of the Bessel function of the first kind, representing the angular location of the first dark ring in the Airy pattern.
Q2: How does numerical aperture affect resolution?
A: Higher NA values result in better resolution as they collect more diffracted light from the specimen.
Q3: What are typical wavelength values?
A: Visible light ranges from ~0.4 μm (violet) to 0.7 μm (red). Common values are 0.55 μm (green) or 0.45 μm (blue).
Q4: Can resolution be better than this calculation?
A: This is the theoretical diffraction limit. Super-resolution techniques can surpass it, but conventional light microscopy cannot.
Q5: Why divide by 2 in the denominator?
A: The factor of 2 accounts for the fact that resolution depends on the half-angle of light collection by the objective.