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laser pointer

n. A device that emits a highly concentrated beam of light to highlight items of interest at some distance

Laser pointer

A laser pointer or laser pen is a small handheld device with a power source (usually a battery) and a laser diode emitting a very narrow coherent low-powered laser beam of visible light, intended to be used to highlight something of interest by illuminating it with a small bright spot of colored light. Power is restricted in most jurisdictions not to exceed 5 mW.

The small width of the beam and low power of typical laser pointers make the beam itself invisible in a reasonably clean atmosphere, only showing a point of light when striking an opaque surface. Some higher-powered laser pointers project a visible beam via scattering from dust particles or water droplets along the beam path. Higher-power and higher-frequency green or blue lasers may produce a beam visible even in clean air because of Rayleigh scattering from air molecules, especially when viewed in moderately-to-dimly lit conditions. The intensity of such scattering increases when these beams are viewed from angles near the beam axis. Such pointers, particularly in the green-light output range, are used as astronomical-object pointers for teaching purposes.

The low-cost availability of infrared (IR) diode laser modules of up to 1000 mW (1 watt) output has created a generation of IR-pumped, frequency doubled, green, blue, and violet diode-pumped solid-state laser pointers with visible power up to 300 mW. Because the invisible IR component in the beams of these visible lasers is difficult to filter out, and also because filtering it contributes extra heat which is difficult to dissipate in a small pocket "laser pointer" package, it is often left as a beam component in cheaper high-power pointers. This invisible IR component causes a degree of extra potential hazard in these devices when pointed at nearby objects and people.

Laser pointers make a potent signaling tool, even in daylight, and are able to produce a bright signal for potential search and rescue vehicles using an inexpensive, small and lightweight device of the type that could be routinely carried in an emergency kit.

If aimed at a person's eyes, laser pointers can cause temporary disturbances to vision. There is some evidence of rare minor permanent harm, but low-powered laser pointers are not seriously hazardous to health. They may be a major annoyance in some circumstances. A dot of light from a red laser pointer may be thought to be due to a laser gunsight. When pointed at aircraft at night, laser pointers may dazzle and distract pilots, and increasingly strict laws have been passed to ban this.

Usage examples of "laser pointer".

Ricci indicated it from his chair with the beam of his pen-sized laser pointer, feeling queerly as if something of the wicked Megan Breen's persona had rubbed off on him.

Mako used a laser pointer to indicate the small, holographic representations of the ships in question.

Cracken used a laser pointer to indicate a star system in the upper right quadrant, which expanded as the pointer's red beam touched the holo's sizing node.

They gathered around while Butler sketched a diagram in the snow with a laser pointer.

He touched the miner's hutch with a laser pointer and enlarged the view.

Doug picked up his laser pointer and aimed its red spot at one of the icons lining the top of the wall screen on his left.

After a while, he took the laser pointer from his pocket, waving it to make a jiggly red dot beside the kittens.

He scaled it, flashed a laser pointer at the video surveillance camera to blind it, and then walked in, nodding at a man in checked chef pants who was sipping a drink near the burners.

Tombstone pointed back toward the large-screen display, then fished in his pocket and pulled out a laser pointer.

He was totally mystified by what she was doing as she pulled out what looked like a laser pointer, aimed it at the orange size planet floating in the middle of the field and squeezed.

He dropped the laser pointer into the sleeve of his silks, walked over to his spot and sat down.

The laser pointer called attention to irregularities on the command ship's hull.