LASER SAFETY AND PRECAUTIONS EXAM
FULL QUESTIONS AND CORRECT ANSWERS
UPDATED COMPLETE REVIEW
●● Why are open beam set ups less common in industrial settings?
Answer: Changing apparatus parameters not really needed
●● Spontaneous emission
Answer: the random emission of a photon due to an atomic electron
moving to a lower energy state
all directions, different phases, polarizations, half life dependent on
transition
●● Stimulated emission
Answer: the process in which an incoming photon causes an excited
atom to drop to a lower energy level, thereby emitting a photon in the
same direction as the incident photon
same direction, phase, polarization
●● Population inversion
,Answer: With two energy levels, more molecules will be in ground state
than excited state for all temperatures
More atoms can be in the excited state if there are more than 3 energy
levels
●● What are the components of a laser?
Answer: Laser active medium/Gain medium: atoms/molecules that can
be excited to metastable state
Excitation system/Energy Pump: intense source of light, radio frequency
voltage generator, high density electric current, other laser
Optical resonant activity: fully reflecting one end, partially reflecting
other end, standing waves needed to generate more photons
●● What are the two types of lasers?
Answer: Gas lasers: He-Ne, CO2, Argon ion, N2
Diode lasers: uses a semiconductor
Fibre lasers: Diode pump laser, doped fibre
, Diode Pumped Solid State Laser (DPSSL)
●● What are the characteristics of light?
Answer: Reflection: specular (wavelength > irregularities), diffuse
(wavelength < irregularities)
Refraction: light can change direction when passing from one material to
another, allows for stray beams to form
Diffraction and Interference: QM reference
Polarization: Circular, elliptical, linear; can occur thru reflection and
birefringence
●● Radiant energy units
Answer: J, energy emitted by laser
●● Radiant power
Answer: W, power emitted by laser
●● Beam diameter
Answer: mm, how wide the beam is
FULL QUESTIONS AND CORRECT ANSWERS
UPDATED COMPLETE REVIEW
●● Why are open beam set ups less common in industrial settings?
Answer: Changing apparatus parameters not really needed
●● Spontaneous emission
Answer: the random emission of a photon due to an atomic electron
moving to a lower energy state
all directions, different phases, polarizations, half life dependent on
transition
●● Stimulated emission
Answer: the process in which an incoming photon causes an excited
atom to drop to a lower energy level, thereby emitting a photon in the
same direction as the incident photon
same direction, phase, polarization
●● Population inversion
,Answer: With two energy levels, more molecules will be in ground state
than excited state for all temperatures
More atoms can be in the excited state if there are more than 3 energy
levels
●● What are the components of a laser?
Answer: Laser active medium/Gain medium: atoms/molecules that can
be excited to metastable state
Excitation system/Energy Pump: intense source of light, radio frequency
voltage generator, high density electric current, other laser
Optical resonant activity: fully reflecting one end, partially reflecting
other end, standing waves needed to generate more photons
●● What are the two types of lasers?
Answer: Gas lasers: He-Ne, CO2, Argon ion, N2
Diode lasers: uses a semiconductor
Fibre lasers: Diode pump laser, doped fibre
, Diode Pumped Solid State Laser (DPSSL)
●● What are the characteristics of light?
Answer: Reflection: specular (wavelength > irregularities), diffuse
(wavelength < irregularities)
Refraction: light can change direction when passing from one material to
another, allows for stray beams to form
Diffraction and Interference: QM reference
Polarization: Circular, elliptical, linear; can occur thru reflection and
birefringence
●● Radiant energy units
Answer: J, energy emitted by laser
●● Radiant power
Answer: W, power emitted by laser
●● Beam diameter
Answer: mm, how wide the beam is
