Untitled Document

Physics Demo Number: 188

Approximate

Run Time: 5 min

Laser Hologram of Telephone Handset

Demo Description

A 35mm slide contains a holographic image of a telephone handset .

The hologram may be displayed on a screen by shining a laser beam through the slide at a grazing angle indicated by arrows on the slide holder.

Scientific Principles

Holograms may be retrieved from flat pieces of film by interference effects with a laser beam.

Equipment

35mm Slide
5 mw Diode Demonstration Laser
Lid to Kit (019), with dedicated vertical mounting block

Equipment Location

Dedicated holder and slide on [C-2-4]
Laser on [C-2-4]
[C-2-4]

Instructions

The slide is seen in the photo.

An elegant holder for the slide has been designed and constructed with the help of the Science Shop.

One can rotate the slide about a perpendicular axis through its center, as well as about a horizontal axis orthogonal to the first axis.

Moreover one may translate the center point of the slide along a vertical line.

The mounted slide is seen in the next photo, along with the diode laser.

The next photo shows the lid to Kit (019) with dedicated vertical mounting block.

The following photo shows the components in use.

A clearer view of the previous photo (more room lights on) is seen in the next photo.

Notice that the slide itself has been flipped over in the holder from its orientation in photos two and one, so that the direct image of the hologram on a screen is not left-right reversed.

The apparatus gives one a rapid set-up capability, but the adjustments are quite exacting and probably require a short relearning 'hands on practice time' for each semesters presentation.