CLT Laser Physics & Safety 2 — Questions and Answers
Question 1: Which laser parameter describes the beam's ability to maintain a fixed phase relationship over time?
- Temporal coherence (Correct answer)
- Spatial coherence
- Divergence
- Polarization
Correct answer: Temporal coherence
Temporal coherence refers to the phase correlation of a light wave with itself over time, related to the laser's spectral purity.
Question 2: A Class 3R laser has a maximum output power of up to how many milliwatts for visible wavelengths?
- 1 mW
- 5 mW (Correct answer)
- 50 mW
- 500 mW
Correct answer: 5 mW
Class 3R lasers emit up to 5 mW in the visible spectrum and present a limited risk if viewed briefly without optical aids.
Question 3: What does the acronym ANSI stand for in the context of laser safety standards?
- American National Standards Institute (Correct answer)
- Association for Networked Safety Initiatives
- Applied Numerical Safety Index
- Accredited National Standards in Imaging
Correct answer: American National Standards Institute
ANSI (American National Standards Institute) publishes the Z136 series of standards governing safe use of lasers in the US.
Question 4: In laser physics, what term describes the minimum time the laser takes to emit a pulse?
- Pulse width (duration) (Correct answer)
- Repetition rate
- Duty cycle
- Rise time
Correct answer: Pulse width (duration)
Pulse width (or pulse duration) is the time interval during which a pulsed laser emits energy, typically measured in nanoseconds or femtoseconds.
Question 5: Which type of hazard is NOT directly associated with laser use?
- Ionizing radiation (Correct answer)
- Fume and plume inhalation
- Fire and explosion
- Electrical hazard
Correct answer: Ionizing radiation
Lasers emit non-ionizing radiation; ionizing radiation (X-rays, gamma rays) is not produced by standard laser systems.
Question 6: What is the function of a beam dump in a laser setup?
- To safely absorb stray or terminated laser beams (Correct answer)
- To amplify the laser output
- To measure beam divergence
- To modulate the pulse rate
Correct answer: To safely absorb stray or terminated laser beams
A beam dump is an optical device designed to absorb and dissipate laser energy from stray or unwanted beams without reflections.
Question 7: The output wavelength of an Nd:YAG laser is primarily at which value?
- 694 nm
- 1064 nm (Correct answer)
- 532 nm
- 10,600 nm
Correct answer: 1064 nm
The fundamental output of an Nd:YAG laser is 1064 nm (near-infrared); it can be frequency-doubled to 532 nm.
CLT Laser Physics & Safety 2
Which laser parameter describes the beam's ability to maintain a fixed phase relationship over time?