The term "laser" actually stands for "light amplification by stimulated emission of radiation". The first laser, which used a silver-coated ruby cylinder as a resonator, was developed in the 1960s at California's Hughes Research Laboratories. Today, lasers are used for a variety of things, from measurement to reading encrypted data, and there are several ways to manufacture lasers, depending on budget and capabilities.
Step
Part 1 of 2: Understanding How Lasers Work
Step 1. Provide a source of energy
Lasers work, or "lasers", by stimulating electrons to emit light of a certain wavelength. (The process was first suggested in 1917 by Albert Einstein.) In order to emit light, electrons must first absorb energy in order to be propelled into a higher orbit, and then release that energy as light upon returning to their original orbit. This energy source is called a “pump”.
- Small lasers, such as those in CD and DVD players and laser pointers, use an electrical circuit to provide electric current to a diode, which acts as a pump.
- The carbon dioxide laser is pumped by an electric current to stimulate the electrons.
- Excimer lasers get energy from chemical reactions.
- Lasers made of crystal or glass use a strong light source such as an arc lamp or flash lamp.
Step 2. Channel the energy through the amplifying medium
The amplifying medium, or active laser medium, amplifies the energy released by the beam due to the stimulated electrons. The reinforcing medium can be one of the following:
- Semiconductors made of materials such as gallium arsenide, aluminum gallium arsenide, or indium gallium arsenide.
- The ruby cylinder-like crystal used in the first laser made by Hughes Laboratories. Sapphires and pomegranates, as well as optical glass fibers, have also been used. The glass and crystals are treated with ions of rare earth metals.
- Ceramics, which are also pretreated with rare earth metal ions.
- A liquid, usually a dye, although infrared lasers are produced using a gin and tonic as the amplifying medium. Gelatin dessert (Jell-O) has also been used successfully as a strengthening medium.
- Gases, such as carbon dioxide, nitrogen, mercury vapor, or a helium-neon mixture.
- Chemical reaction.
- Electron spotlight.
- Nuclear matter. The first uranium laser was created in November 1960, six months after the first ruby laser was created.
Step 3. Adjust the mirrors to accommodate the light
The mirror, or resonator, retains the beam in the laser chamber until it reaches the desired energy level for discharge, either through a small opening in one of the mirrors or through a lens.
- The simplest resonator setup, the linear resonator, uses two mirrors placed opposite each other in the laser chamber. This setting produces a single beam of light.
- A more complicated arrangement, the ring resonator, uses three or more mirrors. This arrangement can produce a single beam, with the aid of an optical isolator, or a double beam.
Step 4. Use a focusing lens to direct the beam through the amplifying medium
Together with the mirror, the lens helps to focus and direct the light so that the amplifying medium gets as much light as possible.
Part 2 of 2: Making Lasers
Method One: Making a Laser from a Laser Device
Step 1. Find a shop that sells laser devices
You can go to an electrical store or search the internet for a “laser device”, “laser module” or “laser diode”. The laser device should include:
- controller circuit. (This part is sometimes sold separately from other components.) Look for a control circuit that will allow you to regulate the amperage.
- Laser diodes.
- Lens, glass or plastic, which can be adjusted. Usually, the diode and lens are packaged together in a small tube. (These components are sometimes sold separately from the controller circuit.)
Step 2. Assemble the controller circuit
Many laser devices require you to build your own controller circuit. This type of device includes a circuit board and related parts, and you must solder them together, according to the schematic that came with the device. However, there are also other devices that have a built-in control circuit.
- You can also design the controller circuit yourself, if you have the electronics expertise to do so. The LM317 controller circuit is a great template for designing your own circuit. Make sure you use a resistor-capacitor circuit so that the energy generated does not radiate excessive pulses.
- After constructing the controller circuit, test it by connecting it to a light-emitting diode (LED). If the LED does not light up immediately, adjust the potentiometer. If the problem persists, double-check the circuit and make sure all parts are properly connected.
Step 3. Connect the controller circuit with the diode
If you have a digital multimeter, connect it to the circuit to monitor the current received by the diode. Most diodes can accommodate a range of 30-250 milliamperes (mA), while a range of 100-150 mA will produce a fairly strong beam.
Although a more powerful beam from the diode will produce a more powerful laser, the additional current required to create the beam will burn and damage the diode more quickly
Step 4. Connect the power source (battery) to the controller circuit
The diode should be shining bright now.
Step 5. Adjust the lens to focus the laser beam
If you want to highlight a wall, adjust it until a nice bright spot appears.
After setting the lens properly, place a matchstick in the laser path and adjust the lens until the match head begins to smoke. You can also try blowing up balloons or punching holes in the paper with a laser
Method Two: Making Lasers from Used Diodes
Step 1. Get a used DVD or Blu-Ray writer
Look for a unit with a write speed of 16x or faster. The unit has a diode with an output power of 150 milliwatts (mW) or greater.
- DVD writer has a red diode with a wavelength of 650 nanometers (nm).
- The Blu-Ray writer has a blue diode with a wavelength of 405 nm.
- The DVD writer should be capable enough to write discs, though it doesn't have to be successful. (In other words, the diode should still work).
- Do not use a DVD reader, CD writer, or CD reader to replace the DVD writer. DVD readers have red diodes, but not as powerful as DVD writers. The CD writer's diode is quite powerful, but emits light in the infrared range, so you'll have to look for beams that you can't see.
Step 2. Take the diode from the DVD/Blu-Ray writer device
Flip device. There are four or more screws that must be removed before the device can be opened and the diode can be removed.
- Once the device is opened, there will be a pair of metal frames held in place by screws. The frame holds the laser components. After removing the screws, you can remove the frame and remove the laser components.
- Diodes are smaller than coins. The diode has three metal legs, and can be encased in a metallic layer, with or without a transparent protective window, or it can be open.
- You have to take the diode from the laser component. To make things easier, first remove the heat sink from the laser component before attempting to remove the diode. If you have an antistatic wrist strap, wear it when you pick up the diode.
- Handle the diode with care, even more carefully if it is an open diode. Prepare an antistatic case to store the diodes until you are ready to manufacture the laser.
Step 3. Get a focusing lens
The beam of the diode must pass through the focusing lens in order to produce a laser. You can do this in one of the following two ways:
- Use a magnifying glass as a focus. Move the magnifying glass until you find the right spot to produce the laser beam, and this should be done every time you want to use the laser.
- Get a lens tube kit with a low-power laser diode, such as 5 mW, and replace it with a diode from a DVD writer.
Step 4. Get or build a controller circuit
Step 5. Connect the diode to the controller circuit
Connect the positive lead of the diode to the positive lead of the controller circuit, and the negative lead to the negative lead. The location of the diode pins varies depending on whether you are using a red diode from a DVD writer or a blue diode from a Blu-Ray writer.
- Hold the diode with the legs facing you, rotating it so that the bases of the legs form a triangle pointing to the right. On both diodes, the top leg is the positive leg.
- On the red diode of the DVD writer, the leg in the middle, which forms the apex of the triangle is the negative leg.
- On the blue diode of the Blu-Ray writer, the lower leg is the negative leg.
Step 6. Connect the power source to the controller circuit
Step 7. Adjust the lens to focus the laser beam
Tips
- The smaller you focus the laser beam, the more powerful the laser will be, but it will only be effective at that focal length. If focused at a distance of 1 m, the laser is only effective at a distance of 1 m. When you don't want to use the laser, disperse the focus of the lens until the laser beam is about the diameter of a ping pong ball.
- To protect your laser device, store it in a receptacle, such as an LED flashlight or battery holder, depending on how small your controller circuit is.
Warning
- Do not shine the laser at a surface that reflects light. Lasers are beams of light and can be reflected just like unfocused beams, only with greater consequences.
- Always wear goggles that are specific to the wavelength of the laser beam you are working with (in this case, the wavelength of the laser diode). The laser goggles are manufactured in colors that balance the color of the laser beam: green for the 650 nm red laser, red-orange for the 405 nm blue laser. Do not use welding helmets, ribbed glasses, or sunglasses in place of laser goggles.
- Do not look into the laser beam source or shine the laser into people's eyes. Class IIIb lasers, the type of laser discussed in this article, can damage the eye, even with the use of laser goggles. Indiscriminately shining a laser beam is also an act of lawlessness.
