---
title: "Laser Cavity Stability calculator — AperiOptic"
description: "Stability parameter g₁·g₂ for a two-mirror cavity. Free online optics calculator, with the formula and code snippets."
url: "https://aperioptic.com/calculators/laser-cavity-stability"
---

# Laser Cavity Stability calculator

Stability parameter g₁·g₂ for a two-mirror cavity.

Category: [Laser & Ultrafast](https://aperioptic.com/calculators)

Formula: `0 ≤ (1-L/R₁)(1-L/R₂) ≤ 1`

## Inputs

| Input | Parameter | Unit | Default |
| --- | --- | --- | --- |
| Length L | `L` | mm | 500 |
| R₁ | `R1` | mm | 1000 |
| R₂ | `R2` | mm | 1000 |

## Result with the default inputs

- g₁·g₂: 0.25
- Stable?: ✓ yes

Open it with your own values: put each input in the address as a parameter, for example [`/calculators/laser-cavity-stability?L=500`](https://aperioptic.com/calculators/laser-cavity-stability?L=500). A unit other than the listed one goes in `<parameter>_unit`.

Read more: [Wikipedia: Optical cavity, Stability](https://en.wikipedia.org/wiki/Optical_cavity#Stability)

[All optics calculators](https://aperioptic.com/calculators)

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The interactive page: https://aperioptic.com/calculators/laser-cavity-stability (AperiOptic runs in the browser; free, no account). Every page of the site as Markdown: https://aperioptic.com/llms.txt