Bloomberg Businessweek USA - 02.09.2019

By E. Tammy Kim

Photograph by Daniel Shea

Night Vision Binoculars

Night vision technology has become reliable and widespread,

used by everyone from soldiers to birders. Although a digital

approach is becoming popular, light intensification remains the

industry standard. As moonlight reflected off an object enters

these battery-powered binoculars, it passes through the lens into

an image-intensifying tube. A photocathode then converts the light

into electrons that are amplified by a photomultiplier and directed

toward a phosphorescent screen to produce a visible image.

When light, in the form of

photons, hits the high-

voltage intensifier tube, it

interacts with a negatively

charged photocathode

normally made of alkali

metals (sodium, potassium,

and cesium) or metalloids

such as antimony.

May contain

or require

PRODUCT COURTESY NIGHT OWL OPTICS, FIRST TEXAS PRODUCTS LLC

The metals transfer energy

from the light particles to

electrons that, with the help of

the battery, are aimed at the

screen. We see the resulting

image in green, which has a

wavelength of 532 nanometers.

The glass lens (silicon

dioxide) is chemically

treated to absorb and

channel as many light

particles as possible.

6

C

Carbon

7

N

Nitrogen

8

O

Oxygen

1

H

Hydrogen

3

Li

Lithium

11

Na

Sodium

14

Si

Silicon

15

P

Phosphorus

19

K

Potassium

51

Sb

Antimony

55

Cs

Cesium

PROP STYLIST: ANNA SURBATOVICH

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