Understanding Lasers: Chapter 8 Quiz
Source: Jeff Hecht, Understanding Lasers: An Entry-Level Guide, fourth edition (2019), Chapter 8 quiz, printed pages 297–299. The questions are paraphrased.
Quick answers
Question |
Answer |
|---|---|
1 |
c, GaAs diode laser |
2 |
b, flashlamp |
3 |
a, 808-nm diode |
4 |
c, chlorine |
5 |
e |
6 |
d, ytterbium |
7 |
a |
8 |
b, \(347\ \mathrm{nm}\) |
9 |
c, \(477\ \mathrm{nm}\) |
10 |
a, titanium–sapphire |
11 |
d |
12 |
e, erbium |
13 |
d, OPSL/VECSEL |
14 |
b, titanium–sapphire |
Worked reasoning
Brief solution
1. Reasoning and answer.
Not in the conventional solid-state category: c. This book treats electrically injected semiconductor diode lasers separately from lasers whose dopant ions are embedded in a dielectric solid host.
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Not in the conventional solid-state category: c. This book treats electrically injected semiconductor diode lasers separately from lasers whose dopant ions are embedded in a dielectric solid host.
Brief solution
1. Reasoning and answer.
Best listed general pump: b. A flashlamp supplies intense broadband light overlapping absorption bands; a properly wavelength-matched diode would usually be better, but none is offered in this item.
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Best listed general pump: b. A flashlamp supplies intense broadband light overlapping absorption bands; a properly wavelength-matched diode would usually be better, but none is offered in this item.
Brief solution
1. Reasoning and answer.
Best neodymium pump: a. An \(808\ \mathrm{nm}\) diode overlaps a strong Nd absorption band, giving efficient, selective pumping.
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Best neodymium pump: a. An \(808\ \mathrm{nm}\) diode overlaps a strong Nd absorption band, giving efficient, selective pumping.
Brief solution
1. Reasoning and answer.
Not an active ion: c. Neodymium, titanium, chromium, and ytterbium are established solid-state laser dopants; chlorine is not one of the active species described.
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Not an active ion: c. Neodymium, titanium, chromium, and ytterbium are established solid-state laser dopants; chlorine is not one of the active species described.
Brief solution
1. Reasoning and answer.
Glass-host advantage: e. Glass is readily fabricated in large rods, slabs, and fibres, although its thermal conductivity is generally poorer than that of crystalline hosts.
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Glass-host advantage: e. Glass is readily fabricated in large rods, slabs, and fibres, although its thermal conductivity is generally poorer than that of crystalline hosts.
Brief solution
1. Reasoning and answer.
Quasi-three-level system: d. Ytterbium’s lower laser level is close enough to the ground state to be thermally populated, so reabsorption must be overcome.
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Quasi-three-level system: d. Ytterbium’s lower laser level is close enough to the ground state to be thermally populated, so reabsorption must be overcome.
Brief solution
1. Reasoning and answer.
Thin-disk pumping: a. Diode light enters through the broad disk face, often making multiple passes, while the thin geometry efficiently removes heat through the back surface.
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Thin-disk pumping: a. Diode light enters through the broad disk face, often making multiple passes, while the thin geometry efficiently removes heat through the back surface.
Brief solution
1. Reasoning and answer.
Ruby second harmonic: b.
2. Key calculation.
\[\lambda_2=\frac{694\ \mathrm{nm}}2=347\ \mathrm{nm}.\]Show detailed steps
Ruby second harmonic: b.
\[\lambda_2=\frac{694\ \mathrm{nm}}2=347\ \mathrm{nm}.\]Brief solution
1. Reasoning and answer.
Not a ready Nd:YAG harmonic: c. Nd:YAG directly gives \(1064\ \mathrm{nm}\); doubling, tripling, and quadrupling give about 532, 355, and \(266\ \mathrm{nm}\). The listed \(477\ \mathrm{nm}\) value is not one of those harmonics.
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Not a ready Nd:YAG harmonic: c. Nd:YAG directly gives \(1064\ \mathrm{nm}\); doubling, tripling, and quadrupling give about 532, 355, and \(266\ \mathrm{nm}\). The listed \(477\ \mathrm{nm}\) value is not one of those harmonics.
Brief solution
1. Reasoning and answer.
Broadest solid-state gain band: a. Titanium–sapphire couples its electronic transition to lattice vibrations and supports a very broad emission band.
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Broadest solid-state gain band: a. Titanium–sapphire couples its electronic transition to lattice vibrations and supports a very broad emission band.
Brief solution
1. Reasoning and answer.
Vibronic distinction: d. Strong interaction between electronic and vibrational states broadens gain, enabling wide tunability and short pulses.
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Vibronic distinction: d. Strong interaction between electronic and vibrational states broadens gain, enabling wide tunability and short pulses.
Brief solution
1. Reasoning and answer.
Least retinal hazard: e. Erbium lasers around \(3\ \mathrm{\mu m}\) are strongly absorbed by water in the cornea and do not focus onto the retina as visible and near-infrared beams do. They remain hazardous to the eye surface.
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Least retinal hazard: e. Erbium lasers around \(3\ \mathrm{\mu m}\) are strongly absorbed by water in the cornea and do not focus onto the retina as visible and near-infrared beams do. They remain hazardous to the eye surface.
Brief solution
1. Reasoning and answer.
Compact separate visible colours: d. Optically pumped semiconductor lasers, also called VECSELs, can be engineered and frequency converted for multiple visible wavelengths.
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Compact separate visible colours: d. Optically pumped semiconductor lasers, also called VECSELs, can be engineered and frequency converted for multiple visible wavelengths.
Brief solution
1. Reasoning and answer.
Femtosecond source: b. Titanium–sapphire’s broad gain bandwidth supports mode-locked pulses lasting only femtoseconds.
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Femtosecond source: b. Titanium–sapphire’s broad gain bandwidth supports mode-locked pulses lasting only femtoseconds.