Calculator Inputs
Formula Used
This calculator links optical power to photon statistics using fundamental constants. It first computes the photon energy, then converts power into photons per second.
- Photon energy from wavelength: E = h·c / λ
- Photon energy from frequency: E = h·f
- Photon rate: Ṅ = P / E
- Photon flux: Φ = Ṅ / A
Optional factors apply as P_effective = P · (throughput) · (duty cycle). For pulsed sources, average power is P_avg = E_pulse · f_rep.
How to Use This Calculator
- Select Continuous or Pulsed mode.
- Enter power, or pulse energy and repetition rate.
- Choose wavelength, frequency, or photon energy input.
- Pick an area method: beam diameter or direct area.
- Set throughput and duty cycle if losses exist.
- Press Calculate to view results above.
- Use the CSV or PDF buttons for quick exports.
Example Data Table
| Mode | Power / Pulse | Wavelength | Diameter | Throughput | Photon Rate (approx.) | Photon Flux (approx.) |
|---|---|---|---|---|---|---|
| Continuous | 10 mW | 532 nm | 1 mm | 1.0 | ~2.7e16 photons/s | ~3.4e22 photons/(s·m²) |
| Pulsed | 1 µJ @ 10 kHz | 1064 nm | 2 mm | 0.9 | ~4.8e16 photons/s | ~1.5e22 photons/(s·m²) |
| Continuous | 1 W | 1550 nm | 5 mm | 0.8 | ~6.2e18 photons/s | ~3.2e23 photons/(s·m²) |
Example outputs are rough and depend on exact constants and conversions.
Photon Flux Guide
1) Meaning of photon flux
Photon flux is the number of photons arriving each second per square meter. It links optical power to counting statistics, photochemistry, and dose planning. This tool reports photon rate (photons/s) and photon flux (photons/(s·m²)).
2) Photon energy sets the scale
Energy per photon comes from constants. With wavelength, E = h·c/λ; with frequency, E = h·f. At 532 nm, photon energy is about 3.7×10-19 J, so 10 mW is roughly 2.7×1016 photons/s.
3) From power to photon rate
After computing photon energy, the calculator divides effective optical power by it: Ṅ = P/E. Effective power can include transmission and modulation factors, matching the light that reaches your target.
4) Area turns rate into flux
Flux is photon rate divided by illuminated area: Φ = Ṅ/A. Because area scales with diameter squared, spot size dominates. Shrinking a beam from 5 mm to 1 mm raises flux by 25×.
5) Continuous and pulsed sources
Continuous sources use average power directly. Pulsed sources use Pavg = Epulse·f, then compute photon rate and flux. The tool also estimates photons per pulse, and peak photon rate when pulse width is given.
6) Efficiency factors you can defend
Throughput (0–1) represents optical transmission and coupling. Duty cycle (0–1) represents gating or chopping. Multiplying them prevents overestimating delivered photons and improves comparison between setups.
7) Planning measurements and detectors
Multiply photon flux by collection area to get photons/s reaching a sensor, then apply quantum efficiency to estimate electrons/s. High flux can saturate detectors, while low flux can be noise-limited.
8) Reporting and reproducibility
Export CSV or PDF after each run to document results. Save wavelength, area method, and efficiency settings alongside the outputs. Consistent records make comparisons across alignments and optics changes straightforward.
FAQs
1) What is the difference between photon rate and photon flux?
Photon rate is total photons per second. Photon flux is photons per second per square meter, so it includes spot size. Flux is better for comparing intensity at a surface.
2) Should I use wavelength or photon energy as input?
Use wavelength when you know the laser line or filter band. Use photon energy when working in electronvolts or when wavelength is uncertain. Both methods produce the same photon energy internally.
3) How do I choose the target area?
Use beam diameter for a circular spot and the tool converts it to area. Use direct area when you already know the illuminated area, such as a measured footprint or sensor aperture.
4) What does throughput represent?
Throughput approximates transmission and coupling losses, from 0 to 1. Example: two 90% mirrors and an 80% filter gives about 0.90×0.90×0.80 ≈ 0.65.
5) How are pulsed results computed?
Pulse energy and repetition rate are converted to average power, then photon rate and flux are computed. The tool also estimates photons per pulse and can estimate peak photon rate if pulse width is provided.
6) Why is my photon flux extremely large?
Small areas create large flux values because the same photons are concentrated into less area. Double-check diameter units and confirm you did not enter micrometers when you meant millimeters.
7) Can I estimate detector counts from photon flux?
Yes. Multiply photon flux by collection area to get photons/s into the detector, then multiply by throughput and quantum efficiency to estimate electrons/s or counts/s.