---
title: "Grating Pair Pulse Compression calculator — AperiOptic"
description: "GDD of a parallel grating pair (Treacy), first order, single pass and double pass. Free online optics calculator, with the formula and code snippets."
url: "https://aperioptic.com/calculators/grating-pair-pulse-compression"
---

# Grating Pair Pulse Compression calculator

GDD of a parallel grating pair (Treacy), first order, single pass and double pass.

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

Formula: `GDD = −λ³·G/(2π·c²·d²·cos³β) · sin β = λ/d − sin θi`

## Inputs

| Input | Parameter | Unit | Default |
| --- | --- | --- | --- |
| Wavelength | `lam` | nm | 800 |
| Separation G (normal) | `Lg` | cm | 20 |
| Groove period | `d` | µm | 1 |
| Incidence angle | `th` | deg | 50 |

## Result with the default inputs

- GDD single pass: -181647.8304 fs²
- GDD double pass: -363295.6607 fs²
- Diffraction angle β: 1.9459 °

Open it with your own values: put each input in the address as a parameter, for example [`/calculators/grating-pair-pulse-compression?lam=800`](https://aperioptic.com/calculators/grating-pair-pulse-compression?lam=800). A unit other than the listed one goes in `<parameter>_unit`.

Read more: [Wikipedia: Chirped pulse amplification](https://en.wikipedia.org/wiki/Chirped_pulse_amplification)

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

---

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