Fresnel Regime Classifier
Calculate aperture Fresnel number and classify it with a caller-supplied regime threshold.
Description
Fresnel number compares aperture size with wavelength times propagation distance.
Fresnel number compares aperture size with wavelength times propagation distance. A supplied threshold divides near-field and far-field labels.1
Calculate aperture Fresnel number and classify it with a caller-supplied regime threshold.
When to use Fresnel Regime Classifier
Use this tool to calculate aperture Fresnel number and classify it with a caller-supplied regime threshold.
Prepare the optical measurements, geometry, fitted coefficients or caller-selected thresholds requested. Confirm wavelength, radius/diameter, pulse-width, angle and unit conventions before running the calculation.
How to use Fresnel Regime Classifier and understand its results
- Prepare the optical measurements, geometry, fitted coefficients or caller-selected thresholds requested. Confirm wavelength, radius/diameter, pulse-width, angle and unit conventions before running the calculation.
- Enter apertureRadiusMeters, propagationDistanceMeters, wavelengthMeters, nearFieldThreshold using the field table and calculation rules, then run the tool.
- Read fresnelNumber, regime. The explanation below defines the units, signs, ordering and any flags or placeholder values.
- If the tool reports an input issue, correct the values and run it again. Apply the stated assumptions when interpreting a successfully returned result.
| Input field | Meaning | Value type; see rules below | Requirement |
|---|---|---|---|
| apertureRadiusMeters | Aperture radius (m) | number; minimum: 0 | Required |
| propagationDistanceMeters | Propagation distance (m) | number; minimum: 0 | Required |
| wavelengthMeters | Wavelength (m) | number; minimum: 0 | Required |
| nearFieldThreshold | Near-field Fresnel threshold | number; minimum: 0 | Required |
Enter nonnegative radius/threshold and positive distance/wavelength. Return number and near-field at equality or above.
number=radius²/(distance×λ) Units, indexing, boundary conditions and exceptional cases are defined in the calculation rules above.
| Output field | Meaning | Value type |
|---|---|---|
| fresnelNumber | Fresnel number | number; minimum: 0 |
| regime | Diffraction regime | string; one of "near-field", "far-field" |
{
"input": {
"apertureRadiusMeters": 0.001,
"propagationDistanceMeters": 10,
"wavelengthMeters": 0.000001,
"nearFieldThreshold": 1
},
"output": {
"fresnelNumber": 0.1,
"regime": "far-field"
}
}Limitations and assumptions
No diffraction pattern or universal regime threshold is supplied.
Numeric inputs must be finite. Follow the calculation-specific rules for overflow, underflow and exceptional cases. Missing required fields, extra fields, wrong value types and violations of the calculation rules are input errors.
Alternative or Complementary methods
Use Spatial-Filter Pinhole: Calculate an Airy-diameter spatial-filter pinhole size with relay magnification. For a complementary task, use Focused-Beam Waist Location: Propagate a Gaussian beam q parameter through a thin lens to locate the new waist.
References
-
Fresnel Regime Classifier — tool.io
Similar or alternative tools
- Spatial-Filter Pinhole
Calculate an Airy-diameter spatial-filter pinhole size with relay magnification.
- Focused-Beam Waist Location
Propagate a Gaussian beam q parameter through a thin lens to locate the new waist.