Laser Physics & Types Flashcards
7 cards from real CLT practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Laser Physics & Types flashcards as text
Which phenomenon allows a fiber laser to achieve very high beam quality despite a long, coiled gain medium?
Answer: Single-mode waveguiding by the fiber core
The fiber core acts as a single-mode waveguide, inherently selecting the fundamental mode and producing excellent beam quality regardless of fiber length or coiling.
What is intracavity frequency doubling (second harmonic generation) used for in laser systems?
Answer: Converting part of the fundamental wavelength to half the wavelength inside the resonator
Intracavity SHG places a nonlinear crystal inside the resonator to convert photons at frequency ω to photons at 2ω, producing a shorter output wavelength.
In a vertical-cavity surface-emitting laser (VCSEL), what is the primary direction of light emission relative to the wafer surface?
Answer: Perpendicular (surface-normal)
VCSELs emit light perpendicular to the wafer surface through distributed Bragg reflector (DBR) mirrors stacked above and below the active region.
Which parameter describes how quickly a laser beam spreads as it propagates away from the beam waist?
Answer: Beam divergence angle
Beam divergence angle (often expressed as half-angle θ) quantifies how rapidly the beam diameter increases with propagation distance beyond the waist.
What is the Rayleigh range of a Gaussian laser beam?
Answer: The propagation distance over which the beam area doubles from the waist
The Rayleigh range z_R = πw₀²/λ is the distance from the beam waist at which the beam radius increases by a factor of √2, doubling the cross-sectional area.
A Nd:YAG laser emitting at 1064 nm is classified as operating in which spectral region?
Answer: Near-infrared
1064 nm falls in the near-infrared (NIR) region, which spans approximately 750 nm to 2500 nm.
Which laser transition in CO2 produces the dominant 10.6 µm emission line?
Answer: Vibrational transition from the 00¹1 to 10⁰0 level of the CO2 molecule
CO2 lasing occurs via a vibrational transition of the CO2 molecule from the antisymmetric stretch mode (00¹1) to the symmetric stretch mode (10⁰0), emitting at 10.6 µm.