Lasers
What does LASER stand for?
The word LASER is an acronym. It stands for Light Amplification by the Stimulated Emission of Radiation. By "radiation", however, the acronym refers to a radiant vibration, not an emission of radioactive particles. In other words, the emissions of lasers are in the form of light, and the frequencies can range anywhere from infra-red to ultraviolet. Those lasers of interest to the laser display industry, however, are mostly those whose output is visible (from red to deep blue).

How do they work?
Lasers work through a process called stimulated emission. The lasers that are typically employed for display are ion gas lasers, because they utilize a gas or a mixture of gases as the lasing medium. The stimulation comes in the form of electricity, which excites the atoms of the gas: as the electrons in these atoms receive more energy, they tend to jump to a higher orbit. These unnaturally high orbits, however, don't last long, and the electrons fall back to their proper orbital shells, to be once again excited by the influx of electricity. It is this process of the electrons returning to their original orbits that creates the laser light we see.
During this jump back down, the extra energy is released from each atom as a packet called a photon (light). Moreover, if this photon collides with another already excited atom, that atom is also stimulated to emit a photon...but this new photon will be vibrating perfectly in step (in-phase) with the colliding photon, and will be traveling on the exact same course.
Photons naturally release in haphazard directions. In order to get them aligned into the tight beam of light with which we're familiar, the tubes in which the atoms of gas are excited must be mirrored on both ends. Any photon that now happens to randomly travel exactly perpendicular with the mirrors on both ends (which inevitably happens) will cause a remarkable chain of events: This begins with the photon's 'cloning' when it bounces off the mirror and collides with another excited atom. Those two in-phase photons then collide with two more excited atoms, making four photons traveling in-phase, and exactly down the length of the laser tube.
This process is then repeated in a geometric progression of photons parading exactly down the laser tube, colliding with more excited atoms, creating more photons, reflecting off the mirrors, and repeating and amplifying the process over and over again. The laser light we see emits through the front mirror, whose reflective coating is partially transparent. In this way, a small percentage of those perfectly aligned photons escape, forming the thin, straight, coherent, beams we call LASER light.

Are lasers safe?
Lasers can be eye-safe, up to a certain level. Beyond a certain level, lasers are definitely eye hazards. There are procedures followed by professional companies to prevent damage, which include filing variance paperwork and complying with the guidelines agreed to by the CDRH and the International Laser Display Association.
Lasers emitting less than 5 mW of light-called Class IIIa lasers by the CDRH-do not require any paperwork. For lasers above 5 mW, the company must file for a variance with the CDRH. The CDRH grants a variance to use lasers for entertainment purposes in return for the user's pledge to follow safety guidelines. Some states require that the laser operator carry a license or permit for laser operation and comply with that state's set of safety standards.

Can we scan the audience?
The ultimate in beautiful, intense, laser atmospheric effects is reaching out and touching the audience with laser light. This is audience scanning. There is a danger inherent here: the light from a laser beam can be strong enough to damage the eye. However, if the laser beam moves rapidly enough through the air, its power disperses over a sufficiently large area to eliminate eye danger.
In the United States, government regulations generally do not allow audience scanning. Atmospheric effects and laser beams can be no closer to an audience than three meters above the floor.
In other countries, such as Germany, companies use audience scanning effects in conjunction with light sensors and fail-safe scanning interlocks that shut off the beam immediately if there is a safety hazard.

Who regulates lasers?
Laser Safety is regulated by different authorities in each country. In Canada the Radiation Protection Bureau (RPB) regulates lasers. In the United States the Center for Devices and Radiological Health [CDRH] regulates lasers.

Why do you need a projector?
The laser produces a single beam of light. To bend or reposition that beam, you need a projector. Using tiny moving mirrors, a single beam of laser light moves so fast the human eye no longer sees the individual beam. Instead, the audience sees fans, cones, tunnels or cascades of beams that fill the air.
When using a white light laser, the projector modulates the beam through a polychromatic acousto-optic modulator (PCAOM) to change colors. Specialized optics (diffraction gratings) can create spectacular sheets of light by splitting one beam into hundreds of individual shafts of light. Bounce mirrors can ricochet beams throughout a venue.
Realistic wire-frame images scanned onto walls, buildings and even mountains advertise products or tell a dramatic story. Wispy, cloud-like graphics called lumia can fill ceilings, and psychedelic abstract graphics can be created with eye-popping colors and contrast.

How do you get colors?
Different gases produce different colors of light, as specific frequencies. Argon gas, for instance, produces colors ranging from emerald green to beautiful deep blues. Krypton gas produces a palette from deep reds to light blues.
A laser incorporating a mixture of these two gases can produce all the colors unique to those individual gases... simultaneously. Krypton/Argon (Ar/Kr) mixed-gas ion lasers are common in laser projection hardware. The beams from the combined Ar/Kr ion laser combine to form a "white" beam; or a white light laser.
Color control can be either subtractive - where unwanted colors are subtracted from the beam, or additive where colors are added to make the desired color. The polychromatic acousto-optic modulator (PCAOM) uses additive color method to produce color. To be very technical, the PCAOM is a solid state, in-line device that allows for continuous brightness control of multiple laser lines generated at 16.7 million or more colors at MHz speeds. It acts as a bulk diffraction grating, which gives brightness control over the individual laser lines. Just as a TV set combines variable brightness of Red, Green and Blue to make the different colors, the PCAOM allows for variable brightness control of a number of laser lines (colors) that are added to create the desired output for projection. For example, one can combine 100% of the red line(s) with 50% of the green line(s) to produce an orange beam.

What are atmospheric effects?
Using the laser's output as a sculptural element in space is what is commonly referred to as "atmospheric" effects. The beam can be static (beams) or kinetic (scans). Beams: These do not move but switch on and off (with and without bounce mirrors).
Typically, static beams emanate from a beam table. Static beams can be the most dangerous type of laser effects; therefore, a minimum safe distance from the viewing area is required. Scans: scans are usually generated by X-Y scanning systems and include fans of beams, beam sequences, sheets of laser, cones and tunnels of beams and some diffraction grating effects that produce beams. These effects require high power lasers, haze or particulate in the air, dim lighting and other environmental controls.

Can I sync the laser display to my music?
Syncing output is achieved through a variety of methods depending on your needs, budget and equipment. Image Engineering ® creates graphics and atmospheric shows to customer supplied soundtracks, existing music, or special edits. In addition, we can match laser output to theatrical cues and DMX or MIDI signals.

How much does it cost?
The answer varies depending on the scope of your project. A good rule of thumb to guage pricing is to remember that a laser show is dependant on three factors: equipment, labor, and studio production time. The more complex the show is in any of these three components, the higher the cost.
For instance, a large outdoor show will require a higher power laser. Additional lasers may be necessary to cover a larger area. More technicians will be necessary to accomodate the increase of equipment. Custom animation of laser graphics will involve studio time to produce. This event could cost thousands of dollars.
Conversely, a single projector that plugs into 110 power, suitable for an indoor event, requires only a single technician.

Pyrotechnics
Is it safe?
In short, pyrotechnics is an art best left to professionals who can insure the effect is as safe as possible. By nature pyrotechnics involve fire and explosion. Both of these are highly dangerous. Safety standards developed by the industry and approved by the ATF insure minimal risk. Our technicians are certified, licensed operators and train each year in current safety procedures. We work closely with local fire authorities to guarantee the least exposure to potential hazards. On site, our staff works with your talent to inform them of proper safety procedures.

Is there debris?
Debris from pyrotechnics depends on the quality of product and type of effect. While some pyrotechnicians will claim there will be no debris from their effects that is not a guaranteed fact. What we do to minimize the likelihood of debris involves testing of various products from the manufacturer, and using only top quality products. If debris is an issue, such as over a basketball court, personnel should be ready to sweep the floor before use.

How much smoke does the pyro create?
Smoke output depends on the effect used, and the amount and duration of use. Indoor pyrotechnics emit minimal smoke by design. A test performed before the show with fire marshals and event staff assesses the quantity of smoke and the aesthetics involved.

Smoke
Does it give off an odor?
There is a slight odor near the source of traditional foggers. It is not harmful. CO2 foggers produce no odor.

Will it leave a residue?
Oil based hazers and foggers can leave a residue. It is highest at the source of the effect and dissapates as it travels through the room. CO2 units do not leave a residue.

Can you produce colored smoke?
Pyrotechnic smoke creates true colored smoke. The dyes used to tint this smoke can also deposit pigment onto your stage sets. In events where this option is not applicable, technicians employ colored lights to tint theatrical smoke.

What is the difference between smoke, fog and haze?
Smoke, generally produced in usual methods, is not suitable for most indoor stage/event applications. Fog and haze machines produce a non-toxic vapor that simulates smoke. These devices handle the majority of temporary installation applications. Fog, produced by chilled vapor hangs low to the ground. Haze is translucent particulate matter introduced to an indoor environment to facilitate visibility of lighting effects.

What sort of "smoke" is available?
There are at least five different sorts of smoke/fog/mist used in theatre, pyrotechnic smoke, smoke machines, CO2, liquid nitrogen foggers, and cracked oil foggers.
Pyrotechnic smoke is the only effect that produces colored smoke. It is also real smoke and can trigger sensors in your building. All precautions and licenses applicable to pyrotechnics apply to this effect.
Professional smoke machines use an electric pump to feed juice from an external tank into a heated chamber. The liquid becomes a vapor "smoke." The electrically pumped machines tend to give a lot more control than consumer grade foggers.
The smoke will hang in the air for a time, depending on the ventilation of the building and the formula of smoke fluid. Smoke from a smoke machine can't be colored, but the dense white smoke takes color from lighting well or the room can be filled with haze.
Hazing the room produces a very pale smoke. It is not as obvious as normal smoke, until you shine light through it. This technique of "hazing" a room is useful when stage lighting or laser atmospherics are present.
Dry-ice or CO2 effects utilize a dry-ice smoke kettle. This is a sealed plastic box with water and electric heating elements in the bottom, and a metal basket containing the dry ice descends into water. The dry ice sublimes to produce a very dense white water-vapor smoke. The smoke flows out of a nozzle on the front of the kettle. Dry-ice smoke is very dense and low-lying. It is also power consumptive. This type of process consumes about 7 or 8 kW of power for a medium sized kettle.
Liquid nitrogen effects work by manipulating conditions of temperature, pressure, and humidity to create areas which hold more water vapor than they are allowed to under normal atmospheric conditions. This is the same type of atmospheric manipulation which leads to the natural formation of clouds, foggy days, and mist formation over ponds and other bodies of water. The difference in this case is that you are able to choose when and where your clouds will appear. This is done by distributing pressurized LN2 to effect heads and spraying LN2 directly into the atmosphere. As LN2 is sprayed from the nozzle, it vaporizes and drives humidity in the surrounding air below dew point. When the dew point threshold is crossed, the humidity condenses into tiny droplets. These droplets are the fog and it is created in just the same way as clouds are created: humidity driven below dew point condenses into fog. Once the fog increases in temperature and the droplets evaporate, the fog disappears leaving nothing behind. The fog is white and takes the color or any reflected light, it has no odor or negative health effect and leaves no residue in the air. It is water condensed in the air to create a brief, visual punctuation to events or performances. LN2 fog is common at fixed installations, such as theme parks or casino stage shows.
Cracked oil foggers produce a nearly transparent haze that scatters light well. Beams of light are clearly visible in the haze, but the haze itself isn't visible. These machines are more expensive than traditional smoke machines and are especially useful in low/no smoke requirement venues.