Fabry-Perot Calculator
Enter mirror reflectivities and cavity length. The Fabry-Perot Calculator instantly computes finesse, free spectral range, linewidth, transmission, and resonance conditions.
About the Fabry-Perot Calculator
The Fabry-Perot Calculator is a precise, scientifically accurate tool that computes all key parameters of a Fabry-Pérot interferometer or optical cavity using the standard formulas from classical optics and laser physics. This Fabry-Perot Calculator implements the exact expressions for finesse, free spectral range (FSR), transmission peaks, linewidth, and resonance conditions — essential for spectroscopy, lasers, and optical filters. Proudly supported by Agri Care Hub.
Scientific Formulas
Finesse: F = π √R / (1 - R) (for R₁ = R₂ = R)
Linewidth (FWHM): Δν = FSR / F
Peak Transmission: T_max = 1 (ideal lossless)
Resonance condition: 2L = m λ
Why This Calculator Is Essential
Fabry-Pérot interferometers are used in: • High-resolution spectroscopy • Laser mode selection and stabilization • Gravitational wave detection (LIGO) • Optical filters and etalons • Telecom (DWDM channels) • Astronomical instruments Finesse determines resolution, while FSR sets the mode spacing — both critical for performance.
How to Use
- Enter mirror reflectivity R (same for both for symmetric case).
- Enter cavity length L in meters.
- Enter operating wavelength λ in nm.
- Click “Calculate Fabry-Perot”.
When Should You Use This Tool?
- Spectroscopy instrument design
- Laser cavity analysis
- Optical filter specification
- Gravitational wave detector modeling
- Telecom channel spacing
- Teaching interference and resonators
Scientific Foundation
The Fabry-Pérot interferometer was invented by Charles Fabry and Alfred Pérot in 1899. The formulas are derived from multiple-beam interference and are exact for plane waves and lossless mirrors. Finesse and FSR are standard figures of merit. Full theory at Fabry-Perot on Wikipedia and Hecht’s *Optics*.
Conclusion
The Fabry-Perot Calculator brings professional optical resonator analysis to your browser — with perfect accuracy and beautiful design. Whether you’re a student learning interference, a researcher designing high-resolution spectrometers, or an engineer building telecom filters, this tool delivers precise results every time. For more optics tools, visit Agri Care Hub.
