CLT Laser Physics & Types 2

Question 1

Which laser type uses a mixture of helium and neon gases to produce a red beam at 632.8 nm?

Accepted Answer

He-Ne laser

Answer

The helium-neon (He-Ne) laser emits a characteristic red beam at 632.8 nm by exciting neon atoms via energy transfer from metastable helium atoms.

Question 2

What is the term for the process in which an excited atom releases a photon spontaneously without external stimulation?

Accepted Answer

Spontaneous emission

Answer

Spontaneous emission occurs when an excited atom returns to a lower energy state and releases a photon without any triggering event.

Question 3

In a semiconductor diode laser, what confines the light within the active region?

Accepted Answer

The p-n junction's refractive index difference

Answer

The difference in refractive index between the active p-n junction layer and the surrounding cladding layers creates a waveguide that confines light.

Question 4

Which laser medium produces emission in the mid-infrared range and is widely used for cutting and welding metals?

Accepted Answer

CO2 laser

Answer

The CO2 laser emits at 10.6 µm in the mid-infrared and is highly absorbed by metals, making it ideal for industrial cutting and welding.

Question 5

What property distinguishes laser light from ordinary white light in terms of phase relationship?

Accepted Answer

Coherence

Answer

Laser light is coherent, meaning all photons share the same phase, frequency, and direction, unlike the random phases of ordinary light.

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