science

Solid-state laser

Solid-state laser is a science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Solid-state laser rather than just read about it. In short: A solid-state laser is a laser that uses a gain medium that is a solid, usually a crystal or glass. Semiconductor-based lasers such as laser diodes are generally excluded, treated as a separate class of laser.

Key takeaways

Solid-state laser belongs to science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Solid-state laser to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Solid-state laser from memory before moving on to harder problems.

Reference excerpt

A solid-state laser is a laser that uses a gain medium that is a solid, usually a crystal or glass. Semiconductor-based lasers such as laser diodes are generally excluded, treated as a separate class of laser.

Solid-state media

Generally, the active medium of a solid-state laser consists of a glass or crystalline "host" material, to which is added a "dopant" such as neodymium, chromium, erbium, thulium, or ytterbium. Many of the common dopants are rare-earth elements, because the excited states of such ions are not strongly coupled with the thermal vibrations of their crystal lattices (phonons), and their operational thresholds can be reached at relatively low intensities of laser pumping. There are many hundreds of solid-state media in which laser action has been achieved, but relatively few types are in widespread use. Of these, probably the most common is neodymium-doped yttrium aluminum garnet (Nd:YAG). Neodymium-doped glass (Nd:glass) and ytterbium-doped glasses or ceramics are used at very high power levels (terawatts) and high energies (megajoules), for multiple-beam inertial confinement fusion. The first material used for lasers was synthetic ruby crystals. Ruby lasers are still used for a few applications, but they are no longer common because of their low power efficiencies. At room temperature, ruby lasers emit only short pulses of light, but at cryogenic temperatures they can be made to emit a continuous train of pulses. The second solid-state gain medium was uranium-doped calcium fluoride. Peter Sorokin and Mirek Stevenson at IBM's laboratories in Yorktown Heights (US) experimented with this material in the 1960s and achieved lasing at 2.5 μm shortly after Maiman's ruby laser. Some solid-state lasers can be made tunable by using intracavity etalons, prisms, gratings, or a combination of these. Titanium-doped sapphire is widely used for its broad tuning range, 660 to 1080 nanometers. Alexandrite lasers are tunable from 700 to 820 nm and yield higher-energy pulses than titanium-sapphire lasers because of the gain medium's longer energy storage time and higher damage threshold.

Pumping

Solid state lasing media are typically optically pumped, using either a flashlamp or arc lamp, or by laser diodes. Diode-pumped solid-state lasers tend to be much more efficient and have become much more common as the cost of high-power semiconductor lasers has decreased.

Mode locking Mode locking of solid-state lasers and fiber lasers has wide applications as large-energy ultra-short pulses can be obtained. There are two types of saturable absorbers that are widely used as mode lockers: SESAM, and SWCNT. Graphene has also been used. These materials use a nonlinear optical behavior called saturable absorption to make a laser create short pulses.

Applications

Solid state lasers are used in research, medical treatment, and military applications, among others. Passively Q-switched solid-state lasers prove useful for ranging, three-dimensional imaging, photoablation, and laser-induced breakdown spectroscopy.

See also Disk laser Laser construction Solid-state dye lasers

References

Koechner, Walter (1999). Solid-State Laser Engineering (5th ed.). Springer. ISBN 978-3-540-65064-5.

Illustrations

Worked examples

Example 1 — a first encounter with Solid-state laser

Start with the simplest possible case. Write down what Solid-state laser claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Solid-state laser before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Solid-state laser ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Solid-state laser

In research: Solid-state laser appears in science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Solid-state laser in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Solid-state laser is common in secondary-school and first-year university syllabi. It links to neighbouring topics Solid-state lasers, so understanding it makes those chapters shorter.
In everyday life: Look for Solid-state laser outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

Affiliate

Preply — study more efficiently by working with a personal tutor. 50% off.

How to study Solid-state laser in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Solid-state laser means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Solid-state laser out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Solid-state laser in simple terms?

Why does Solid-state laser matter?

Because it connects several science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Solid-state laser?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Solid-state laser.