# How the First Laser Was Invented

> The foundational 1960 patent by Schawlow and Townes that describes how to amplify light waves to create a laser, moving beyond microwave technology.

- **Patent:** US 2929922
- **Original title:** Masers and maser communications system
- **Owner:** Bell Telephone Laboratories Inc
- **Granted:** 1960
- **Status:** Public domain (expired)
- **Times cited:** 145
- **Field:** telecommunications, semiconductors, consumer_electronics

## What it does

This patent describes the transition from masers, which amplify microwaves, to optical masers, which we now call lasers. It details the use of a resonant cavity with reflective ends to trap light, allowing it to bounce back and forth through an active medium. This process stimulates the emission of more light, creating a highly focused, single-color beam. It essentially provides the blueprint for using light as a precise tool for communication and energy transmission.

## What it does NOT cover

- Does not cover the use of semiconductor materials for lasers, which were developed later.
- Does not cover fiber optic cables themselves, only the light-amplification device.
- Does not cover non-resonant methods of light amplification.

## The clever bit

The inventors realized that by using a long, thin cavity with mirrors at the ends, they could force light to travel in a single, coherent direction, effectively turning a chaotic light source into a powerful, directed beam.

## Real-world examples

1. Fiber optic communication networks
2. Laser eye surgery
3. Barcode scanners
4. Laser pointers

## Why it matters

This patent is widely considered the birth certificate of the laser. It turned a theoretical physics concept into a practical device that now powers everything from internet fiber optics to medical surgery and barcode scanners.

## Frequently asked questions

### What does How the First Laser Was Invented cover?

The foundational 1960 patent by Schawlow and Townes that describes how to amplify light waves to create a laser, moving beyond microwave technology.

### Who owns patent US 2929922?

Bell Telephone Laboratories Inc owns this patent, granted in 1960.

### When does this patent expire?

This patent has expired and is now in the public domain — anyone can use the invention freely.

### What is patent US 2929922 cited by?

This patent has been cited by 145 later patents that build on its ideas.

### What problem does this patent solve?

This patent is widely considered the birth certificate of the laser. It turned a theoretical physics concept into a practical device that now powers everything from internet fiber optics to medical surgery and barcode scanners.

### What does this patent NOT cover?

Does not cover the use of semiconductor materials for lasers, which were developed later.

**Full plain-English explainer:** https://patentbrief.org/patent/us/2929922/laser-maser

**Original patent:** https://patents.google.com/patent/US2929922

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_Source: PatentBrief — https://patentbrief.org. Patent facts are from public records; the plain-English explanation is PatentBrief's._


## Related patents

Semantically similar inventions in the PatentBrief corpus:

- [Gordon Gould's Early Concepts for High-Frequency Radiation Devices](https://patentbrief.org/patent/us/3388314/laser-gordon-gould) — A 1968 patent by Gordon Gould describing methods to generate and amplify radiation at frequencies exceeding visible light, building on his foundational laser work.
- [How Marconi Patented Early Wireless Telegraphy Signals](https://patentbrief.org/patent/us/586193/radio-wireless-marconi) — Guglielmo Marconi's 1897 patent for sending electrical signals through the air to enable early wireless communication.
- [How James Russell Invented the Digital Optical Disc](https://patentbrief.org/patent/us/3501586/optical-digital-recording-russell) — A 1966 invention that replaced physical needles on vinyl records with a laser beam reading digital data from a spinning disc.
- [How the First Infrared LED Was Invented](https://patentbrief.org/patent/us/3293513/infrared-led-biard-pittman) — Texas Instruments' 1962 patent for the first practical semiconductor diode that emits infrared light when electricity passes through it.
- [How Laser Printers Use Rotating Mirrors to Write Information](https://patentbrief.org/patent/us/3867571/laser-printer-starkweather) — A 1972 Xerox patent describing how to use a spinning mirror to scan a laser beam across a page, adjusting the speed of the data to keep the image sharp.