Estimate etendue, efficiency, and photon delivery for optics. Compare NA and f-number quickly. Export clean reports for engineering reviews today.
| Scenario | Pin (mW) | λ (nm) | D (mm) | NA | Total throughput | Pout (mW) |
|---|---|---|---|---|---|---|
| Lab alignment baseline | 10 | 532 | 25 | 0.22 | ≈ 0.58 | ≈ 5.8 |
| Added filter, lower coupling | 10 | 532 | 25 | 0.22 | ≈ 0.40 | ≈ 4.0 |
| Higher NA acceptance | 10 | 532 | 25 | 0.35 | ≈ 0.58 | ≈ 5.8 |
Optical throughput is commonly tracked as etendue, the product of aperture area and acceptance solid angle. For an air cone, Ω ≈ πNA² and A = π(D/2)², so G = A·Ω grows with D² and NA². Doubling aperture diameter increases G by 4×, while increasing NA from 0.20 to 0.30 raises Ω by (0.30/0.20)² = 2.25×. This calculator reports G in m²·sr for direct comparisons across designs.
Engineering reviews often separate element transmission (coatings, windows, filters) from geometric efficiency (coupling, fill factor, obscuration). Multiplying factors provides Tsys, a compact metric for delivered power. A chain of 96%, 99%, 92%, and 98% yields 0.96×0.99×0.92×0.98 ≈ 0.858. If coupling is 70%, the overall becomes ≈ 0.601 before any additional margins.
Many optical interfaces specify acceptance by NA, while imaging optics are commonly described by f-number. For small angles in air, NA ≈ 1/(2F#). A system at f/2.0 implies NA ≈ 0.25, and f/4.0 implies NA ≈ 0.125. Consistent definitions prevent overestimating acceptance, especially when translating between lens and fiber specifications.
Photon flux supports quick feasibility checks for shot-noise limits. Using Φ = Pλ/(hc), a delivered power of 1 mW at 532 nm gives roughly 2.68×10¹⁵ photons/s. At longer wavelengths, the same power yields more photons because each photon carries less energy. Pair flux estimates with detector quantum efficiency for electron rate projections.
The reported irradiance E = P/A is a useful sanity check for damage thresholds and alignment procedures. For example, 5 mW through a 25 mm aperture corresponds to E ≈ 10 W/m². If your system concentrates light further downstream, evaluate peak intensity at the focus separately, because this calculator describes the aperture plane, not focal spot power density.
Early designs often carry limited measurement data. The optional relative uncertainty band applies a simple ± percentage to output power and photon flux to communicate sensitivity. Use it to represent combined tolerances from coating variance, alignment drift, and contamination. For critical programs, replace this with a formal Monte Carlo budget using measured distributions.
It refers to etendue G = A·Ω and the system throughput Tsys that scales delivered power. Together they describe acceptance and loss.
For a small-angle cone in air, the accepted solid angle is well-approximated by πNA². It is a practical engineering estimate.
Use NA mode for fibers, light guides, and acceptance cones. Use f/# when your specification is lens-based and you want NA ≈ 1/(2F#).
Not explicitly. Enter measured or vendor transmission for each optical group to capture multi-surface reflectance and coating effects.
Use your expected alignment and mode-matching efficiency, including connector repeatability. If uncertain, start with 50–80% and refine.
It reports aperture-plane irradiance only. For focused spot intensity, compute focal spot size and divide delivered power by spot area.
Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.