Bloomberg Businessweek USA - 02.09.2019

42

By E. Tammy Kim

Photograph by Daniel Shea

Laser

Lasers are both potent and

mundane, high-energy beams

that can be used to operate

on eyes, precision-cut metal

for appliances, and scan

bar codes at the corner

store. “Light amplification

by stimulated emission of

radiation” neatly describes

how the technology works:

Energy is applied to a

medium—such as a crystal

wafer, liquid solution, or

gas—whose particles become

stimulated and emit light.

Mirrors capture and amplify

that light into an intense beam.

A dime-size YAG crystal is

mounted on a finger-shaped

metal device that keeps

the crystal cool. Energy is

pumped through the crystal

to create a powerful laser.

May contain

or require

Clusters of diode lasers provide

energy to the YAG crystal.

These apply electrical current

to wafers of gallium arsenide

wrapped in gold wire.

PRODUCT COURTESY TRUMPF LASERS

There are as many types of lasers

as there are uses for them. The YAG

laser shown here—a crystal of yttrium

aluminum garnet, sprinkled with

ytterbium (neodymium is also often

used)—emits infrared light, whose

wavelength is well suited to welding.

1

H

Hydrogen

2

He

Helium

10

Ne

Neon

6

C

Carbon

7

N

Nitrogen

8

O

Oxygen

9

F

Fluorine

17

Cl

Chlorine

18

Ar

Argon

13

Al

Aluminum

14

Si

Silicon

70

Yb

Ytterbium

60

Nd

Neodymium

79

Au

Gold

33

As

Arsenic

36

Kr

Krypton

31

Ga

Gallium

26

Fe

Iron

29

Cu

Copper

54

Xe

Xenon

39

Y

Yttrium