OSHA LASER SAFETY (TEST) TERMS WELL EXPLAINED #10
Diffuse Reflection - correct answer Takes place when different parts of a beam incident
on a surface are reflected over a wide range of angles in accordance with Lambert's
Law. The intensity will fall off as the inverse of the square of the distance away from the
surface and also obey a Cosine Law of reflection.
Pumping system - correct answer uses photons from another source as a xenon gas
flash tube (optical pumping) to transfer energy to the media, electrical discharge within
the pure gas or gas mixture media (collision pumping)
Laser medium - correct answer can be a solid (state), gas, dye (in liquid), or
semiconductor. Lasers are commonly designated by the type of lasing material
employed.
Solid state - correct answer lasers have lasing material distributed in a solid matrix, e.g.,
the ruby or neodymium-YAG (yttrium aluminum garnet) lasers. The neodymium-YAG
laser emits infrared light at 1.064 micrometers.
Gas - correct answer lasers (helium and helium-neon, hene, are the most common gas
lasers) have a primary output of a visible red light. CO2 lasers emit energy in the far-
infrared, 10.6 micrometers, and are used for cutting hard materials.
Excimer - correct answer lasers (the name is derived from the terms excited and
dimers) use reactive gases such as chlorine and fluorine mixed with inert gases such as
argon, krypton, or xenon. When electrically stimulated, a pseudomolecule or dimer is
produced and when lased, produces light in the ultraviolet range.
Dye lasers - correct answer use complex organic dyes like rhodamine 6G in liquid
solution or suspension as lasing media. They are tunable over a broad range of
wavelengths.
Semiconductor - correct answer lasers, sometimes called diode lasers, are not solid-
state lasers. These electronic devices are generally very small and use low power. They
may be built into larger arrays, e.g., the writing source in some laser printers or compact
disk players.
Absorb - correct answer To transform radiant energy into a different form, with a
resultant rise in temperature.
Absorption - correct answer Transformation of radiant energy to a different form of
energy by the interaction of matter, depending on temperature and wavelength.
Accessible Emission Level - correct answer The magnitude of accessible laser (or
collateral) radiation of a specific wavelength or emission duration at a particular point as
, measured by appropriate methods and devices. Also means radiation to which human
access is possible in accordance with the definitions of the laser's hazard classification.
Accessible Emission Limit (AEL) - correct answer The maximum accessible emission
level permitted within a particular class. In ANSI Z 136.1, AEL is determined as the
product of accessible emission Maximum Permissible Exposure limit (MPE) and the
area of the limiting aperture (7 mm for visible and near-infrared lasers).
Aperture - correct answer An opening through which radiation can pass.
Argon - correct answer A gas used as a laser medium. It emits blue-green light primarily
at 448 and 515 nm.
Attenuation - correct answer The decrease in energy (or power) as a beam passes
through an absorbing or scattering medium.
Aversion Response - correct answer Movement of the eyelid or the head to avoid an
exposure to a noxious stimulant, bright light. It can occur within 0.25 seconds, and it
includes the blink reflex time.
Beam - correct answer A collection of rays that may be parallel, convergent, or
divergent.
Beam Diameter - correct answer The distance between diametrically opposed points in
the cross section of a circular beam where the intensity is reduced by a factor of e-1
(0.368) of the peak level (for safety standards). The value is normally chosen at e-2
(0.135) of the peak level for manufacturing specifications.
Beam Divergence - correct answer Angle of beam spread measured in radians or
milliradians (1 milliradian = 3.4 minutes of arc or approximately 1 mil). For small angles
where the cord is approximately equal to the arc, the beam divergence can be closely
approximated by the ratio of the cord length (beam diameter) divided by the distance
(range) from the laser aperture.
Blink Reflex - correct answer The visual sensation of the luminous intensity of a light
source. The brightness of a laser beam is most closely associated with the radio-metric
concept of radiance.
Carbon Dioxide - correct answer Molecule used as a laser medium. Emits far energy at
10,600 nm (10.6 µm).
Closed Installation - correct answer Any location where lasers are used which will be
closed to unprotected personnel during laser operation.
Diffuse Reflection - correct answer Takes place when different parts of a beam incident
on a surface are reflected over a wide range of angles in accordance with Lambert's
Law. The intensity will fall off as the inverse of the square of the distance away from the
surface and also obey a Cosine Law of reflection.
Pumping system - correct answer uses photons from another source as a xenon gas
flash tube (optical pumping) to transfer energy to the media, electrical discharge within
the pure gas or gas mixture media (collision pumping)
Laser medium - correct answer can be a solid (state), gas, dye (in liquid), or
semiconductor. Lasers are commonly designated by the type of lasing material
employed.
Solid state - correct answer lasers have lasing material distributed in a solid matrix, e.g.,
the ruby or neodymium-YAG (yttrium aluminum garnet) lasers. The neodymium-YAG
laser emits infrared light at 1.064 micrometers.
Gas - correct answer lasers (helium and helium-neon, hene, are the most common gas
lasers) have a primary output of a visible red light. CO2 lasers emit energy in the far-
infrared, 10.6 micrometers, and are used for cutting hard materials.
Excimer - correct answer lasers (the name is derived from the terms excited and
dimers) use reactive gases such as chlorine and fluorine mixed with inert gases such as
argon, krypton, or xenon. When electrically stimulated, a pseudomolecule or dimer is
produced and when lased, produces light in the ultraviolet range.
Dye lasers - correct answer use complex organic dyes like rhodamine 6G in liquid
solution or suspension as lasing media. They are tunable over a broad range of
wavelengths.
Semiconductor - correct answer lasers, sometimes called diode lasers, are not solid-
state lasers. These electronic devices are generally very small and use low power. They
may be built into larger arrays, e.g., the writing source in some laser printers or compact
disk players.
Absorb - correct answer To transform radiant energy into a different form, with a
resultant rise in temperature.
Absorption - correct answer Transformation of radiant energy to a different form of
energy by the interaction of matter, depending on temperature and wavelength.
Accessible Emission Level - correct answer The magnitude of accessible laser (or
collateral) radiation of a specific wavelength or emission duration at a particular point as
, measured by appropriate methods and devices. Also means radiation to which human
access is possible in accordance with the definitions of the laser's hazard classification.
Accessible Emission Limit (AEL) - correct answer The maximum accessible emission
level permitted within a particular class. In ANSI Z 136.1, AEL is determined as the
product of accessible emission Maximum Permissible Exposure limit (MPE) and the
area of the limiting aperture (7 mm for visible and near-infrared lasers).
Aperture - correct answer An opening through which radiation can pass.
Argon - correct answer A gas used as a laser medium. It emits blue-green light primarily
at 448 and 515 nm.
Attenuation - correct answer The decrease in energy (or power) as a beam passes
through an absorbing or scattering medium.
Aversion Response - correct answer Movement of the eyelid or the head to avoid an
exposure to a noxious stimulant, bright light. It can occur within 0.25 seconds, and it
includes the blink reflex time.
Beam - correct answer A collection of rays that may be parallel, convergent, or
divergent.
Beam Diameter - correct answer The distance between diametrically opposed points in
the cross section of a circular beam where the intensity is reduced by a factor of e-1
(0.368) of the peak level (for safety standards). The value is normally chosen at e-2
(0.135) of the peak level for manufacturing specifications.
Beam Divergence - correct answer Angle of beam spread measured in radians or
milliradians (1 milliradian = 3.4 minutes of arc or approximately 1 mil). For small angles
where the cord is approximately equal to the arc, the beam divergence can be closely
approximated by the ratio of the cord length (beam diameter) divided by the distance
(range) from the laser aperture.
Blink Reflex - correct answer The visual sensation of the luminous intensity of a light
source. The brightness of a laser beam is most closely associated with the radio-metric
concept of radiance.
Carbon Dioxide - correct answer Molecule used as a laser medium. Emits far energy at
10,600 nm (10.6 µm).
Closed Installation - correct answer Any location where lasers are used which will be
closed to unprotected personnel during laser operation.
