Calculator Inputs
Use peak field, RMS field, or direct power-area mode. The calculator panel uses 3 columns on large screens, 2 on smaller screens, and 1 on mobile.
Plotly Graph
The chart updates after calculation and visualizes how intensity changes with the selected driving input.
Example Data Table
| Case | Method | Main Inputs | Computed Intensity | Notes |
|---|---|---|---|---|
| Example 1 | Peak field | E0 = 1000 V/m, n = 1.00, λ = 1550 nm | ≈ 1328.13 W/m² | Typical plane-wave estimation in air. |
| Example 2 | RMS field | ERMS = 500 V/m, n = 1.50 | ≈ 995.95 W/m² | Useful for dielectric media studies. |
| Example 3 | Power and area | P = 0.02 W, Area = 2 mm² | 10,000 W/m² | Useful for beam delivery calculations. |
Formula Used
For a uniform optical plane wave, the average optical field intensity is the time-averaged magnitude of the Poynting vector.
1) From peak electric field amplitude
I = 0.5 × n × c × ε₀ × E₀²
2) From RMS electric field
I = n × c × ε₀ × ERMS²
3) From power and beam area
I = P / A
Additional relationships
E₀ = √(2I / (n × c × ε₀))
ERMS = E₀ / √2
f = c / λ
Ephoton = h × f
Photon Flux = I / Ephoton
Where n is refractive index, c is the speed of light, ε₀ is vacuum permittivity, P is optical power, and A is illuminated beam area.
How to Use This Calculator
- Select the input method that matches your available measurement data.
- Enter the refractive index of the propagation medium.
- Provide wavelength if you want photon energy and photon flux outputs.
- Enter peak field, RMS field, or power depending on the selected method.
- Optionally enter beam radius or direct beam area to estimate total power.
- Optionally enter exposure time to compute fluence.
- Press the calculate button to show results above the form.
- Use the CSV or PDF buttons to export the generated results.
Frequently Asked Questions
1. What does optical field intensity represent?
Optical field intensity represents average optical power flow through a unit area. It is commonly reported as irradiance in W/m² or mW/cm² for engineering analysis.
2. When should I use peak electric field input?
Use peak electric field when your source specification or simulation provides wave amplitude directly. This is common in electromagnetic modeling and optical field propagation studies.
3. When is RMS electric field more appropriate?
Use RMS electric field when measurements come from averaged instruments or when equations are expressed in RMS form. It is often easier for practical measurement workflows.
4. Why does refractive index matter?
Refractive index changes wave impedance and therefore changes calculated intensity for a given electric field. The same field amplitude produces different intensity in different media.
5. What is the difference between intensity and power?
Power is total optical energy delivered per second. Intensity is that power distributed over area. You can convert between them if the illuminated beam area is known.
6. Why add wavelength if intensity already exists?
Wavelength lets the calculator derive frequency, photon energy, and photon flux. These outputs help compare beam transport, detector response, and photon-limited designs.
7. What does fluence mean in this calculator?
Fluence is energy per unit area over a chosen exposure time. It is useful for pulsed exposure checks, material processing estimates, and optical safety comparisons.
8. Can I use this calculator for laser beams?
Yes, for first-pass engineering estimates. It assumes a uniform beam over the given area. Strongly nonuniform or Gaussian beams need profile-specific corrections.