1. What Is Optical Resolution?

Optical resolution refers to the ability of an imaging system to distinguish between two closely spaced objects. The Abbe diffraction limit, formulated by Ernst Abbe in 1873, defines the fundamental resolution limit of optical microscopes and other imaging systems.

2. How Does The Abbe Criterion Work?

The calculator uses the Abbe resolution equation:

Where:

• \( \lambda \) — Wavelength of light used (meters)
• \( NA \) — Numerical aperture of the optical system

Explanation: The equation shows that resolution improves with shorter wavelengths and higher numerical apertures. This is why electron microscopes (using much shorter electron wavelengths) achieve much higher resolution than light microscopes.

3. Importance Of Resolution Calculation

Details: Understanding resolution limits is crucial for designing optical systems, selecting appropriate microscopy techniques, and interpreting imaging results in fields like biology, materials science, and semiconductor manufacturing.

4. Using The Calculator

Tips: Enter wavelength in meters (e.g., 550 nm = 5.5e-7 m) and numerical aperture (typically between 0.1 and 1.4 for air and oil immersion objectives). Both values must be positive.

5. Frequently Asked Questions (FAQ)

Q1: What is numerical aperture (NA)?
A: Numerical aperture is a measure of the light-gathering ability of an optical system, defined as NA = n × sin(θ), where n is the refractive index and θ is the half-angle of the maximum cone of light.

Q2: Why is there a resolution limit?
A: The resolution limit arises from the wave nature of light and diffraction effects that blur the image of point objects, creating Airy patterns that overlap when objects are too close.

Q3: Can resolution be better than the Abbe limit?
A: Conventional optical microscopy cannot surpass the Abbe limit, but super-resolution techniques like STED, PALM, and STORM can achieve higher resolution using special methods.

Q4: How does wavelength affect resolution?
A: Shorter wavelengths provide better resolution, which is why ultraviolet and blue light offer higher resolution than red light in optical microscopy.

Q5: What are typical resolution values?
A: For visible light microscopy (λ ≈ 500 nm, NA ≈ 1.4), resolution is approximately 180 nm. Electron microscopes can achieve resolutions down to 0.1 nm or better.