The devil is in the details when making holograms. It make sense since we're taking about making a microscopic recording of the interference pattern of laser light. So tiny errors in your process can render your hologram dim or nonexistant. Below are three tips that will head you toward success in making your first holograms. Read carefully, and remember, pay attention to the details.
Tip 1: Avoid Vibration and Microscopic Movement
Vibration and minute movements during exposure are the main reason holograms don’t turn out. If any part of your holography system moves even one millionth of meter during exposure, your hologram will not likely turn out. So avoid talking, music, noise, walking around, air currents, creaky floors, soft objects, temperature changes to the object. . . . What other things can you think of that might cause vibration?
Many items deform beyond what we can see with the naked eye. This is due to tension, gravity, changes in temperature, and air current, among other things. Avoid using items made of soft plastic, paper, and cardboard when choosing your subject and other parts of your system.
If one is using holographic film instead of plates, know that film is particularly vulnerable to discreet movements and vibration. The film can flutter under air current or shrink and expand due to the heat on your fingers. To address this, sandwich the film between two glass plates fastened by clips, squeeze out any air pockets between the film and the glass plates, and let the film-plate sandwich settle for five minutes.
Given the above, it is understandable why we should find a work area with a sturdy table that is far from noise and vibration (air conditioners, heating vents, noisy traffic outside, etc.). Using a computer mouse pad or tray of sand (or salt or sugar) helps dampen vibration.
Tip 2: Choose Your Subject Wisely
For the subject of your first hologram, we recommend using coins, such as quarters or dimes, since these are bright, hard, and non-deforming. By successfully making one hologram first, you will learn the fundamentals needed to venture onto using other objects.
For your subsequent holograms, the appropriate choice of your subject is critical. In general, your subject should ideally (1) be made of a solid material such metal or porcelain; (2) appear bright when illuminated with the red laser light; and (3) not move or deform.
Try to avoid choosing objects that are fabric or furry objects (e.g. teddy bear), since these objects deform most easily. Try to also avoid large plastic objects as they tend to expand and contract with the slightest change in temperature (even from the heat of your fingers!).
Tip 3: Prepare Your Laser for Holography
Make sure to turn on the laser for at least five minutes before making holograms. Avoid touching the laser for the two minutes just prior to making an exposure, since any disturbance to the laser can potentiall cause it to become unstable. Finally, avoid cross draft (moving air) across the laser. This affects the laser's operational stability needed for making holograms.
If this is your first-time making holograms, we'd highly recommend you use our Integraf holography diode laser. Our diode laser has an adjustable and removable lens, making it easy to spread the beam without any need for an external beam spreader. The laser has been fully tested for the frequency stability and coherence length required for holography.
To make holograms with the Integraf holography diode laser, unscrew the black collimating lens from the front of the Integraf holography diode laser. A small spring behind the lens will pop out. Keep both in a safe place so you can put them back on later (this protects the laser from dirt and dust for future use). Hold the laser by the brass cylinder and avoid touching the exposed circuit board. By removing lens, the beam can shine out much like a flashlight and illuminate an elongated elliptical area. Without any other lens involved, the beam is extra clean and bright.
Whether you are using the Integraf holography diode laser or your own diode laser, we'd recommend powering the diode laser with two D-size batteries (3.0 volts) for best results. Using batteries helps avoid unexpected power surges, thus keeping the laser's frequency necessarily stable for holography. Alternatively but less preferred, you can use other highly stabilized DC power sources with an output of 3.0 volts (or up to 4.5 volts).