Flashcards in Laser Dentistry Deck (143)
What is the height of wave called in EM Spectrum?
What is the distance between 2 corresponding points in a periodic wave called? (the distance a photon travels in one complete oscillation)
What is # of complete oscillations of a wave called? (Cycles/Sec=Hz) also Inverse. proport. to WL
FREQUENCY="Repetition Rate"=Hertz (Hz) (also "Emission Cycles" or "Pulses" per Second)
What is the velocity of a photon?
Speed of Light=186,282 miles/sec (300,000 km/hr)
How Laser Light is different than Visible Light? (Both are EM Radiation, traveling at the speed of light, as a wave and particle)
1) Man-made (doesn't exist in nature)
2) special, unique form of light
3) found in WLs-UV,Visible,IR
What is a Photon?
EM particles associated with light="quanta" of EM energy traveling at the speed of light
Who defined that energy was emitted in quantifiable form?
Max Planck=Quantum Physics=Planck's Constant (h) ="Quanta packets" E=hv E=hc/wl
What physicist developed Quantum Theory="photons"="quanta of light"?
What physicist is responsible for the theory of "Stimulated Emission of Energy"?
if artificially stimulated, excited atoms can absorb "quantum of energy"
Who patented the term LASER?
Gordon Gould in 1957
Who developed the 1st Functional LASER? (credited for 1st LASER) 1st Functional Dental Laser?
1) Theodore Maiman in 1960 (inserted a Ruby Crystal into a photographic flashlamp
2) 1989 - 1st true dental laser
Who created the first LASER?
Charles Townes=MASER=Microwave Amplification by Stimulated Emission of Radiation
Laser Light or Visible Light?
Laser Light or Visible Light?
-collimated ("parallel beam")/monochromatic
-reflected back and forth by precise mirrors
-monochromatic="one wavelength=one color"
-coherent="light waves in phase"
What is the definition of Coherence?
every wave is of the SAME WL/IN PHASE (Amplitudes Aligned)...the photons are well-ordered and travel parallel to each other
What is Amplification? (Amplitudes are aligned="coherent"=thus maximizing wave energies)
a process that occurs in OPTICAL RESONATOR...where stimulated emission produces a population inversion
What part of the dental laser that is responsible for Amplification/Coherence of light waves?
(Collimated Beam+Coherent Energy...responsible for Laser accuracy)
Can you affect the MONOCHROMATICITY and COLLIMATION of Laser Light?
Monochromaticity...can altar WL by passing laser light through "frequency dbling crystals" (i.e. Alexandrite Laser
Collimation...pass laser light through any medium>density than air-see some divergence (i.e. c.f. Lens convergence)
What does LASER acronym stand for?
Light Amplification by Stimulated Emission of Radiation
(atom in a "stimulated" state-stimulated by another quanta of energy...produce 2 "COHERENT quanta of energy"
What are the components of a LASER?
1) Pumping Mech 2) Active Medium
3) Optical Resonator (pumping mech/amplifier)
4) Delivery System 5) Cooling System ("fan") 6) Control System= foot switch/display panel/safety mech
Name 2 types of Pumping Mechanisms in Dental Lasers?
"EXCITATION SOURCE"="EXTERNAL ENERGY SOURCE"
1) FRP (Free running pulsed) = rapidly strobing Flashlamp (Er:YAG,Nd:YAG)
2) CW (Continuous Wave) = Electric Induction Coil (Diode or CO2)
**can be Pulsed or Gated ("Chopped")
Creates...population inversion within the active medium to cause continued stimulated emission of radiation or "Amplified Light" by mechanism to reflect photons back and forth?
OPTICAL RESONATOR = Pumping Mechanism in Dental Laser
3 Types of ACTIVE MEDIUM in dental lasers
1) Liquid=Excimer Dye
2) Gas=CO2 or Argon
a) YAG or YSGG Crystal
b) Diode Capacitor = Al (or IN), Ga, As
What is the "laser cavity" where light AMPLIFICATION occurs?
What are the components within an OPTICAL RESONATOR?
1) Active Medium=Solid, Liquid or Gas
2) Mirrors (for amplification)
Definition of POPULATION INVERSION=
an environment that produces more atoms with electrons in higher energy orbitals that in the ground state...
LASER LIGHT is MONOCHROMATIC, meaning =
only a specific wavelength is preferentially stimulated from the "excited" atoms
LASER LIGHT is COHERENT, meaning =
the wavelengths of the stimulated photons line up with the passing photons
What type of Dental Laser uses a solid crystal active medium "sandwiched" between silicon wafers"
(the crystal is polished to act as mirrors)