HOLOGRAMS WITH LASER LEADER

A hologram difference basically of a normal photography in that not only it registers the distribution of intensities of the reflected light, but also the one of phases. That is to say, the film is able to distinguish between the waves that affect the photosensitive surface being in their maximum amplitude, of that do it with minimum amplitude. This capacity to differentiate waves with different phases is obtained interfering with a beam of reference with the reflected waves.

Thus, in one of the methods of obtaining of holograms, the object is illuminated by means of a beam of coherent light, a beam in which all the waves move to each other in phase and that is generated with a laser. In essence, the form of the object determines the aspect of the fronts of wave, that is to say, the phase with which the reflected light affects each one of the points of the photographic plate. Part of this same beam laser is reflected simultaneously in a mirror or prism and goes towards the photographic plate; this beam denominates reference beam. The fronts of wave of this last one, when not being reflected in the object, remain parallel with respect to the plane and produce a landlord of interference with the fronts of wave of the light reflected by the object. If this one is a point, for example, the fronts of wave of the reflected beam will be spherical; the landlord of interference produced in the film then will be formed by concentric circles, being reduced the space between the circles as it increases the radius.

The landlord of interference produced by a more complicated object also will be much more complex, reason why the simple inspection of the resulting hologram will only discover a complicated landlord of dark and clear structures that apparently they do not bear any relation to the original object. Nevertheless, if the hologram under coherent light is contemplated, the recorded object will be made visible; and if the hologram is contemplated from different angles, the object also is seen from different angles. The three-dimensional effect obtains because the hologram reconstructs in the space the wave fronts that originally were created by the object.

MATERIALS

- JD-2 Kit to reveal films in black and white - Photo-Flo - Fourth dark - Film (the “film” is in fact one thin glass plate.) - PFG-01 sensible Plates - Sharpshooting laser commercial type of 500 mW - Concave Lens 12mm Diam.

Others: 1 Gallon of distilled water - Four bottles of 1-liter (empty) - Three disposable plastic trays - Two plastic glasses - granulated Sugar - Plasticine - Gloves of rubber.

STOPPER

The stopper is a simple cardboard piece with the part inferior cut in the form of tongue-piece so that it does not fall. The device is above Also… Two fasteners for the clothes - Chronometer - Three batteries AA - Two clips cayman jaw - Portapilas ‘AA’ - Piece of table for the base.

SINCE ONE BECOMES

- The laser leader is placed that already is preparation beforehand with external batteries and a switch between two tweezers for clothes. - Glasses with sugar fill both. - The clamp for clothes in sugar is pressed - the lens in the other clamp is placed and everything in the glass with sugar is placed. - If everything is correct, when driving the switch the laser must work. - A quarter is needed completely in the dark to make the exhibition of the sensible plate. We take into account: The smallest amount of light does not have to enter nor. A very solid table or the floor is used. One is not due to do in places where there are sources of vibration (ex. ventilators, refrigerator…) A dishwasher or sink near When choosing is needed objecto for the hologram: Objecto must be solid as plastic or metal - objecto must be smaller than the sensible plate. (7 xs 7 cm) To avoid dark objectos. Something of showy and clear colors must better be if he is metalist. - The toys of plásticico, shells and small statues make good holograms.

The object to the same height is placed that the laser leader. The plate supported on a piece of wood or metal is placed and on the plate the object. The object with platilina in the part can be assured superior. The plate with the fingers is not due to touch. The distance between the lens and the object must be of about 70 cm. Soon aligns the laser. What one looks for is to illuminate the object. We will notice that the ray is not to circulate but almost square. In order to manage to see with more clarity the ray of the laser a white paper between the object and the laser, only for a moment can be placed.

PROCESS

Tests among 6 to 20 seconds with the leader are due to make to find what is the optimal exposure time. All this becomes in the most complete darkness. Soon the plate is taken and is revealed it. The plate with the help of a hair dryer is dried. In this point the hologram already can be seen. In order to observe a lantern or the light of the sun is used it. Other light sources as the fluorescent one causes that the hologram is not seen. If it is desired that the hologram is more shining and is seen better back paints the part of the plate with painting in espray black mate.