Astigmatic Collimator Design
Estimate separate fast- and slow-axis collimator focal lengths from divergence and target diameter.
Description
Astigmatic collimation treats fast and slow axes separately.
Astigmatic collimation treats fast and slow axes separately. Small-angle divergences and a target radius yield two ideal focal lengths.1
Estimate separate fast- and slow-axis collimator focal lengths from divergence and target diameter.
When to use Astigmatic Collimator Design
Use this tool to estimate separate fast- and slow-axis collimator focal lengths from divergence and target diameter.
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 Astigmatic Collimator Design 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 fastAxisDivergenceRadians, slowAxisDivergenceRadians, targetBeamDiameterMillimeters using the field table and calculation rules, then run the tool.
- Read fastAxisFocalLengthMillimeters, slowAxisFocalLengthMillimeters, focalLengthRatio. 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 |
|---|---|---|---|
| fastAxisDivergenceRadians | Fast-axis half divergence (rad) | number; minimum: 0 | Required |
| slowAxisDivergenceRadians | Slow-axis half divergence (rad) | number; minimum: 0 | Required |
| targetBeamDiameterMillimeters | Target collimated beam diameter (mm) | number; minimum: 0 | Required |
Enter positive divergence radians and diameter mm. Return fast/slow focal lengths and slow-to-fast ratio.
f_axis=(targetDiameter/2)/divergence_axis Units, indexing, boundary conditions and exceptional cases are defined in the calculation rules above.
| Output field | Meaning | Value type |
|---|---|---|
| fastAxisFocalLengthMillimeters | Fast-axis focal length (mm) | number; minimum: 0 |
| slowAxisFocalLengthMillimeters | Slow-axis focal length (mm) | number; minimum: 0 |
| focalLengthRatio | Slow-to-fast focal ratio | number; minimum: 0 |
{
"input": {
"fastAxisDivergenceRadians": 0.1,
"slowAxisDivergenceRadians": 0.02,
"targetBeamDiameterMillimeters": 10
},
"output": {
"fastAxisFocalLengthMillimeters": 50,
"slowAxisFocalLengthMillimeters": 250,
"focalLengthRatio": 5
}
}Limitations and assumptions
Divergences must follow the half-angle convention of this formula. No lens design, aberration, source extent or axis coupling is modeled.
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 Beam-Expander Magnification: Calculate signed beam-expander magnification, output diameter, and lens configuration. For a complementary task, use Axicon Bessel Zone: Estimate geometric Bessel-zone length from beam radius and axicon cone angle.
References
-
Astigmatic Collimator Design — tool.io
Similar or alternative tools
- Beam-Expander Magnification
Calculate signed beam-expander magnification, output diameter, and lens configuration.
- Axicon Bessel Zone
Estimate geometric Bessel-zone length from beam radius and axicon cone angle.