LASERS CERTIFICATION EXAM
QUESTIONS AND CORRECT ANSWERS
Theorized the concept of stimulated emission - ✔✔Einstein
Theorized that an excited electron will spontaneously return to its ground state
- ✔✔Bohr
First ruby laser was created in _____ by ______. - ✔✔1960, Ted Maiman
_________ reported in 1965 that a ruby laser could vaporize enamel. - ✔✔Stern
and Sognnaes
First pulsed Nd:YAG laser released in ______ and cuts ______ tissue. - ✔✔1990,
soft tissue
In _____ the first dental hard tissue was FDA cleared and is called _______. And
the ______ laser a year later. - ✔✔1997
Er: YAG laser
Er, Cr: YSGG
The word LASER is an acronym standing for _________. - ✔✔Light Amplification
by Stimulated Emission of Radiation
Laser parameters include what 3 things? - ✔✔1)Duration of exposure
2)Fiber Diameter
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,3)Wavelength
Lasers are:
______chromatic?
_____directional?
coherent or noncoherent?
emitted from a stimulated ____________. - ✔✔monochromatic: made of a
single wavelength (visible or infrared)
unidirectional
coherent (all peaks and valleys of each wave travel in unison)
active medium
What states can the active medium be in? - ✔✔solid, gas, semiconductor
What type of active medium is used in Er: YAG? - ✔✔solid state using crystal
matrix (erbium laced yttrium, aluminum and garnet)
What type of gas is used when the active medium is sealed in an air tight
chamber? - ✔✔CO2
Diode lasers have what type of active medium? - ✔✔semiconductor
what photons form the laser? - ✔✔light that leaks from the output coupler
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, Stimulated emission: - ✔✔atoms of the active medium are stimulated to a
higher energy level--> released as a photon as the atom returns to a more stable
lower energy level.
Amplification - ✔✔Released photons can go on to stimulate more atoms in the
crystal, thus producing more photons
Energy density depends on what 3 things? - ✔✔energy, divergence (tendency of
a laser beam to spread outward=laser beam diameter increases), and distance
Energy is measured in ______ - ✔✔Joules (millijoules)
Power is ______ and is measured in _______ - ✔✔rate of doing work, or energy
used over a period of time and is measured in Watts (J/sec)
Frequency is measured in _____. - ✔✔Hertz ( laser pulses/sec)
What is the most important variable dictating how the laser beam will interact
with the target tissue? - ✔✔Peak Power
Define Peak Power: - ✔✔power level in each individual laser pulse, however it is
not visible to the operator
Describe Peak Power in the 3 types:
1) Continuous
2) Gated
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©JOSHCLAY 2025/2026. YEAR PUBLISHED 2025.
QUESTIONS AND CORRECT ANSWERS
Theorized the concept of stimulated emission - ✔✔Einstein
Theorized that an excited electron will spontaneously return to its ground state
- ✔✔Bohr
First ruby laser was created in _____ by ______. - ✔✔1960, Ted Maiman
_________ reported in 1965 that a ruby laser could vaporize enamel. - ✔✔Stern
and Sognnaes
First pulsed Nd:YAG laser released in ______ and cuts ______ tissue. - ✔✔1990,
soft tissue
In _____ the first dental hard tissue was FDA cleared and is called _______. And
the ______ laser a year later. - ✔✔1997
Er: YAG laser
Er, Cr: YSGG
The word LASER is an acronym standing for _________. - ✔✔Light Amplification
by Stimulated Emission of Radiation
Laser parameters include what 3 things? - ✔✔1)Duration of exposure
2)Fiber Diameter
Page 1 of 19
©JOSHCLAY 2025/2026. YEAR PUBLISHED 2025.
,3)Wavelength
Lasers are:
______chromatic?
_____directional?
coherent or noncoherent?
emitted from a stimulated ____________. - ✔✔monochromatic: made of a
single wavelength (visible or infrared)
unidirectional
coherent (all peaks and valleys of each wave travel in unison)
active medium
What states can the active medium be in? - ✔✔solid, gas, semiconductor
What type of active medium is used in Er: YAG? - ✔✔solid state using crystal
matrix (erbium laced yttrium, aluminum and garnet)
What type of gas is used when the active medium is sealed in an air tight
chamber? - ✔✔CO2
Diode lasers have what type of active medium? - ✔✔semiconductor
what photons form the laser? - ✔✔light that leaks from the output coupler
Page 2 of 19
©JOSHCLAY 2025/2026. YEAR PUBLISHED 2025.
, Stimulated emission: - ✔✔atoms of the active medium are stimulated to a
higher energy level--> released as a photon as the atom returns to a more stable
lower energy level.
Amplification - ✔✔Released photons can go on to stimulate more atoms in the
crystal, thus producing more photons
Energy density depends on what 3 things? - ✔✔energy, divergence (tendency of
a laser beam to spread outward=laser beam diameter increases), and distance
Energy is measured in ______ - ✔✔Joules (millijoules)
Power is ______ and is measured in _______ - ✔✔rate of doing work, or energy
used over a period of time and is measured in Watts (J/sec)
Frequency is measured in _____. - ✔✔Hertz ( laser pulses/sec)
What is the most important variable dictating how the laser beam will interact
with the target tissue? - ✔✔Peak Power
Define Peak Power: - ✔✔power level in each individual laser pulse, however it is
not visible to the operator
Describe Peak Power in the 3 types:
1) Continuous
2) Gated
Page 3 of 19
©JOSHCLAY 2025/2026. YEAR PUBLISHED 2025.
