LASERS CERTIFICATION EXAM QUESTIONS AND
ANSWERS 2023 WITH COMPLETE SOLUTION
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
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
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
3) Free running pulsed
1) the peak power equals the average power displayed
2) Average power is half of peak power
3) Low Average power, very high peak power
What are the two basic forms of pulsed laser modes?
Gated wave
Free running pulsed
How is the gated wave pulse created?
created with a shutter that blocks the laser beam from reaching the handpiece and
target tissue at varying speeds: the laser is on constantly but the shutter device blocks
the light from transmitting. (example: flashlight moving hand in front of it)
How is the Free running pulse created?
Not on constantly, but emit photons in powerful bursts of energy measured in millionths
of seconds.
(example: turning flashlight on and off)
Which lasers operate in continuous mode? (can be mechanically turned into a
gated mode when a shutter is used)
CO2, Diode
Which lasers operate in free running pulsed mode?
Nd:YAG, Erbium lasers
Shorter pulses ______ peak power (increase or decrease?)
Which laser uses shorter pulses?
ANSWERS 2023 WITH COMPLETE SOLUTION
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
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
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
3) Free running pulsed
1) the peak power equals the average power displayed
2) Average power is half of peak power
3) Low Average power, very high peak power
What are the two basic forms of pulsed laser modes?
Gated wave
Free running pulsed
How is the gated wave pulse created?
created with a shutter that blocks the laser beam from reaching the handpiece and
target tissue at varying speeds: the laser is on constantly but the shutter device blocks
the light from transmitting. (example: flashlight moving hand in front of it)
How is the Free running pulse created?
Not on constantly, but emit photons in powerful bursts of energy measured in millionths
of seconds.
(example: turning flashlight on and off)
Which lasers operate in continuous mode? (can be mechanically turned into a
gated mode when a shutter is used)
CO2, Diode
Which lasers operate in free running pulsed mode?
Nd:YAG, Erbium lasers
Shorter pulses ______ peak power (increase or decrease?)
Which laser uses shorter pulses?
