Determine the diameter of a hair sample using laser diffraction patterns and Babinet's Principle.
Measurement Parameters
Calculated Diameter
Enter measurements to calculate hair diameter
Quick Reference
dHair Diameter
mFringe Order
λWavelength
LDistance to Screen
yFringe Offset
Overview
This calculator uses the physics of diffraction to measure the thickness of a hair. According to Babinet's Principle, the diffraction pattern of an opaque object (like a hair) is identical to that of a slit of the same size.
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Pro Tips
Use a stable laser pointer (red is usually 650nm, green 532nm).
The fringe offset 'y' is the distance from the central bright spot to the m-th dark fringe.
Increasing the distance to the screen ('L') makes the pattern larger and easier to measure.
Measuring the distance between multiple fringes and dividing by the count (e.g., 5 fringes) improves accuracy.
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Fun Facts
"Average human hair ranges from 17 to 181 micrometers in diameter."
"Babinet's Principle states that diffraction patterns are the same for complementary apertures."
"Laser diffraction is a standard non-destructive method for measuring fine fibers in industry."
