Table Of ContentМИНИСТЕРСТВО НАУКИ И ВЫСШЕГО ОБРАЗОВАНИЯ
РОССИЙСКОЙ ФЕДЕРАЦИИ
ФЕДЕРАЛЬНОЕ ГОСУДАРСТВЕННОЕ БЮДЖЕТНОЕ
ОБРАЗОВАТЕЛЬНОЕ УЧРЕЖДЕНИЕ
ВЫСШЕГО ОБРАЗОВАНИЯ
«МИРЭА ‐ Российский технологический университет»
(РТУ МИРЭА)
Lasers
Учебно-методическое пособие
Москва 2022
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Lasers [Электронный ресурс]: Учебно-методическое пособие / Кудинова Т.В., Миролюбова
Н.А., Эркенова Д.И. (и др.) – М.: МИРЭА – Российский технологический университет, 2022.
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практического овладения профессиональной терминологией по тематике лазеры.
Рассматриваются основные типы лазеров, осваивается и закрепляется специальная
профессиональная лексика.
Рекомендовано к изданию на заседании кафедры Иностранных языков.
Авторский коллектив:
Кудинова Татьяна Викторовна, старший преподаватель кафедры иностранных языков РТУ
МИРЭА
Миролюбова Наталия Алексеевна, старший преподаватель кафедры иностранных языков
РТУ МИРЭА
Каппушева Инесса Шамильевна, старший преподаватель кафедры иностранных языков РТУ
МИРЭА
Эркенова Джамиля Исмаиловна, ассистент кафедры иностранных языков РТУ МИРЭА
Комарова Маргарита Игоревна, ассистент кафедры иностранных языков РТУ МИРЭА
Рецензенты:
Дерягина Зинаида Савиновна, кандидат филологических наук, доцент, преподаватель
департамента педагогического образования, автономная некоммерческая организация
дополнительного образования.
Васильев Андрей Георгиевич, доктор физико-математических наук, профессор,
директор института радиоэлектроники и информатики (ИРИ).
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TABLE OF CONTENTS
UNIT 1. LASERS .......................................................................................................... 4
Text A. Lasers – fundamentals, design, physics ....................................................... 4
Text B. Types of lasers ............................................................................................ 11
UNIT 2. SOLID-STATE LASERS ............................................................................. 15
Text A. Solid-state lasers ......................................................................................... 15
Text B. Vibronic lasers ............................................................................................ 20
UNIT 3. SEMICONDUCTOR LASERS .................................................................... 23
Text A. Semiconductor lasers ................................................................................ 23
UNIT 4. GAS LASERS ............................................................................................... 29
Text A. Gas lasers .................................................................................................. 29
Text B. Excimer Lasers ........................................................................................... 33
UNIT 5. LIQUID LASERS. SOME APPLICATIONS OF PULSED-LASERS ....... 37
Text A. Liquid lasers. Some applications of pulsed-lasers .................................... 37
UNIT 6. НЕКОТОРЫЕ РЕКОМЕНДАЦИИ ПО СОСТАВЛЕНИЮ
АННОТАЦИЙ И ТЕЗИСОВ..................................................................................... 42
SUPPLEMENTARY READING AND ADDITIONAL TASKS .............................. 51
Translation tasks .......................................................................................................... 65
GLOSSARY ................................................................................................................ 77
REFERENCES ............................................................................................................ 84
INFORMATION ABOUT THE AUTHORS ............................................................. 86
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UNIT 1. LASERS
Text A. Lasers – fundamentals, design, physics
Pre-text task 1. Match laser devices with the Russian equivalents:
1. Laser printer a. 3D лазерное сканирование
2. Laser rangefinder b. Лазерный сканер штрих-кода
3. Laser measure c. Лазерный гироскоп
4. 3D laser scanning d. Лазерный принтер
5. Laser welding e. Лазерный измеритель
6. Laser barcode scanner f. Лазерный локатор (лидар)
7. Laser gyroscope g. Лазерный дальномер
8. Lidar h. Лазерная сварка
Pre-text task 2. Today lasers are widely used in various spheres of our life.
Work in pairs and discuss what these spheres are, what you know about lasers
and principles they are based on.
Fundamentals
Light amplification by stimulated emission of radiation (Laser) is a mechanism
for emitting light within the electromagnetic radiation spectrum via the process of
stimulated emission. The emitted laser light is a spatially coherent, narrow low-
divergence beam that can be manipulated with lenses. In laser technology «coherent
light» is light sources that emits light of in-step waves of identical frequency and
phase. The laser’s beam of coherent light differentiates it from light sources that emit
incoherent light beams, of random phase varying with time and position; whereas the
laser light is narrow-wavelength electromagnetic spectrum monochromatic light; yet,
there are lasers that emit a broad-spectrum light, or simultaneously, at different wave-
lengths. A laser is a device which produces highly directional light. It emits light
through a process called stimulated emission of radiation which increases the intensi-
ty of light. In other words,
1.1 A laser is different from conventional light sources in four ways: coherence,
directionality, monochromaticity, and high intensity.
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1.2 The light waves of ordinary light sources have many wavelengths. Hence,
the photons emitted by ordinary light sources are out of phase. Thus, ordinary light is
incoherent.
1.3 On the other hand, the light waves of laser light have only one wavelength.
Hence, all the photons emitted by laser light are in phase. Thus, laser light is coher-
ent.
1.4 The light waves from laser contain only one wavelength or color so it is
known as monochromatic light.
1.5 The laser beam is very narrow and can be concentrated on a very small area.
This makes laser light highly directional.
1.6 The laser light spreads in a small region of space. Hence, all the energy is
concentrated on a narrow region. Therefore, laser light has greater intensity than the
ordinary light.
Terminology
The first device using amplification by stimulated emission operated at micro-
wave frequencies, and was named «maser», an acronym for «microwave amplifica-
tion by stimulated emission of radiation». When similar optical devices were devel-
oped, they were first known as «optical masers», until «microwave» was replaced by
«light» in the acronym.
All such devices operating at frequencies higher than microwaves are called la-
sers (including infrared laser, ultraviolet laser, X-ray laser and gamma-ray laser). All
devices operating at microwave or lower radio frequencies are called masers.
Types of lasers
Lasers are classified into 4 types based on the type of laser medium used:
• Solid-state laser
• Gas laser
• Liquid laser
• Semiconductor laser
Design
A laser consists of a gain medium inside a highly reflective optical cavity, as
well as a means to supply energy to the gain medium. The gain medium is a material
with properties that allow it to amplify light by stimulated emission. In its simplest
form, a cavity consists of two mirrors arranged such that light bounces back and
forth, each time passing through the gain medium. Typically, one of the two mirrors,
5
the output coupler, is partially transparent. The output laser beam is emitted through
this mirror.
Light of a specific wavelength that passes through the gain medium is amplified,
the surrounding mirrors ensure that most of the light makes many passes through the
gain medium, being amplified repeatedly. Part of the light that is between the mirrors
passes through the partially transparent mirror and escapes as a beam of light.
Fig.1.1
Components of a typical laser:
1. Gain medium
2. Laser pumping energy
3. High reflector
4. Output coupler
5. Laser beam
The process of supplying the energy required for the amplification is called
pumping. The energy is typically supplied as an electrical current or as light at a dif-
ferent wavelength. Such light may be by a flash lamp or perhaps another laser.
Laser physics
The gain medium of a laser is a material of controlled purity, size, concentration
and shape, which amplifies the beam by the process of stimulated emission. It can be
of any state: gas, liquid, solid or plasma. The gain medium absorbs pump energy,
which raises some electrons into higher-energy (excited) quantum states. Particles
can interact with light both by absorbing photons or by emitting photons. Emission
can be spontaneous or stimulated. In the latter case, the photon is emitted in the same
6
direction as the light that is passing by. When the number of particles in one excited
state exceeds the number of particles in some lower-energy state, population inver-
sion is achieved and of stimulated emission due to light that passes through is larger
than the amount of absorption. Hence, the light is amplified. By itself, this makes an
optical amplifier. When an optical amplifier is placed inside a resonant optical cavity,
one obtains a laser.
The light generated by stimulated emission is very similar to the input signal in
terms of wavelength, phase, and polarization. This gives laser light its characteristic
coherence, and allows it to maintain the uniform polarization and often monochroma-
ticity established by the optical cavity design.
The optical cavity, a type of cavity resonator, contains a coherent beam of light
between reflective surfaces so that the light passes through the gain medium more
than once before it is emitted from the output aperture or lost to diffraction or absorp-
tion. As light circulates through the cavity, passing through the gain medium, if the
gain (amplification) in the medium is stronger than the resonator losses, the power of
the circulating light can rise exponentially. But each stimulated emission event re-
turns a particle from its excited state to the ground state, reducing the capacity of the
gain medium for further amplification. When this effect becomes strong, the gain is
said to be saturated. The pump power against gain saturation and cavity losses pro-
duces an equilibrium value of the laser power inside the cavity; this equilibrium de-
termines the operating point of the laser. If the chosen pump power is too small, the
gain is not sufficient to overcome the resonator losses, and the laser will emit only
very small light powers. The minimum pump power needed to begin laser action is
called the lasing threshold. The gain medium will amplify any photons passing
through it, regardless of direction; but only the photons aligned with the cavity man-
age to pass more than once through the medium and so have significant amplifica-
tion.
Task 3. Read and translate text A.
Task 4. Complete the following sentences.
1. The emitted laser light is a spatially coherent, narrow…
2. In laser technology “coherent light” is light sources that…
3. The laser light is narrow-wavelength electromagnetic spectrum…
4. A laser consists of a gain medium…
5. The gain medium is a material with properties that allow…
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6. A cavity consists of two mirrors arranged such that light bounces…
7. The process of supplying the energy required for the amplification…
8. The gain medium absorbs pump energy, which raises some…
9. Lasers are classified into 4 types based on the type of…
10. When an optical amplifier is placed inside a resonant optical cavity…
Task 5. Answer the following questions.
1. What does laser stand for?
2. What does maser stand for?
3. What can you say about the structure of the laser?
4. What is peculiar about one of the laser's mirrors?
5. What is the gain medium?
6. What does one need to start the process of stimulated emission?
7. How is typically the energy supplied to the gain medium?
8. What are the differences between laser and maser?
9. What differs laser light from conventional light sources?
10. What types of lasers do you know?
11. Why is one of the laser’s mirrors partially transparent?
12. What two types of emission do you know?
13. What is pumping?
Task 6. Scan the text to mark the statements below true or false.
1. Laser is a machine that makes an amplified, single-color source of light.
2. Laser is a high-frequency radio wave.
3. Laser means “light absorption in solid environment of ruby”.
4. Laser means “light amplification by stimulated emission of radiation”.
5. Laser and maser are one and the same device.
6. Maser means “microwave amplification by stimulated emission of radia-
tion”.
7. Light amplification by stimulated emission of radiation (laser) is a
mechanism for emitting light within the electromagnetic radiation spectrum via the
process of stimulated emission.
8. The emitted laser light is a spatially incoherent and non-monochromatic.
9. Lasers are classified into seven types based on the type of laser medium
used.
8
10. The laser beam is very narrow and can be concentrated on a very small
area.
Task 7. Find in the text English equivalents of the following words and ex-
pressions:
лазер, луч когерентного света, спектр электромагнитного излучения, ин-
версия населенности, усиление света, вынужденное излучение, спонтанное из-
лучение, источники света, усиление света посредством вынужденного излуче-
ния, полупроводниковый лазер, сильноотражающий оптический резонатор, по-
лостной резонатор, энергия накачки.
Task 8. Give Russian equivalents of the following words and expressions:
wavelength, monochromatic light, solid-state laser, infrared laser, liquid laser,
light amplification by stimulated emission of radiation, electromagnetic radiation
spectrum, microwave amplification by stimulated emission of radiation, gain medi-
um, gas laser, microwave frequencies, ultraviolet laser, laser beam, partially transpar-
ent mirror, optical amplifier.
Task 9. Translate the sentences into English.
1. Усиление света посредством вынужденного излучения (лазер) – это
механизм излучения света в пределах спектра электромагнитного излучения
посредством процесса вынужденного излучения.
2. Лазерный луч когерентного света отличает его от источников света,
которые излучают некогерентные световые лучи со случайной фазой, изменя-
ющейся со временем и положением.
3. Лазер представляет собой монохроматический свет с узкой длиной
волны электромагнитного спектра.
4. Лазер представляет собой активную среду внутри оптического ре-
зонатора с высокой отражающей способностью, а также средства подачи энер-
гии в активную среду.
5. Активная среда лазера – это вещество, свойства которого позволя-
ют ему усиливать свет вынужденным излучением.
6. Окружающие зеркала гарантируют, что большая часть света мно-
жество раз проходит через активную среду, многократно усиливаясь.
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7. Большинство практических лазеров содержат дополнительные эле-
менты, которые влияют на такие свойства, как длина волны излучаемого света
и форма луча.
8. Когда оптический усилитель помещается внутри резонансного оп-
тического резонатора, получается лазер.
9. Это придает лазерному свету характерную когерентность и позво-
ляет ему поддерживать равномерную поляризацию и монохроматичность,
установленные конструкцией оптического резонатора.
10. Если усиление в среде сильнее, чем потери в резонаторе, мощность
циркулирующего света может возрастать экспоненциально.
11. Как правило, одно из двух зеркал – зеркало вывода излучения – ча-
стично прозрачно.
12. Лазер отличается от обычных источников света четырьмя особен-
ностями: когерентностью, направленностью, монохроматичностью и высокой
интенсивностью.
13. Усиливающая среда лазера представляет собой материал контроли-
руемой чистоты, размера, концентрации и формы, который усиливает луч света
в процессе стимулированного излучения.
14. Усиливающая среда лазера может находиться в любом состоянии:
газообразном, жидком, твердом или плазменном.
15. Частицы могут взаимодействовать со светом как путем поглощения
фотонов, так и путем выделения фотонов.
Task 10. Watch a video at
[https://www.youtube.com/watch?v=WJ05XOJiaDY&list=TLPQMTAwMzIw
MjLkscyTEuP5oQ&index=8] and fill in the gaps in the sentences below:
1. The transition electrons don’t stay for longer time in the _____ ______.
2. Such systems are called ________ _______ or _______ _______.
3. When electrons turn into active systems, their ________ _______
________ are also modified and thus it acquires some ________ _________.
4. Generally, electrons exist in lower state called as ________ ________.
5. Due to the process of ________ when ____________ _________ equal
to the difference of E₃ - E₁ are incident on atom, electrons jump from state 1 to the
_______ _______ 3.
6. But some of the electrons may lose very less energy E₃ - E₂ and ______
to ______ E₂.
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