5. Answer the following questions:

1. What is a laser? 2. What is the gain medium of a laser? 3. Can particles of electrons interact with light? 4. Is the output laser beam emitted through the mirror? 5. Does laser consist of a gain medium inside a highly reflective optical cavity? 6.When is the energy supplied? 7. Is photon emitted in the same direction as the light that is passing by? 8. Does laser produce light by itself?

6. Match the first part (1-5) of the sentence with the second part (a-e) :

1. The emitted laser light ...

2. A beam produced by a thermal or other incoherent light source ...

3. Pumping can interact with light by …

4. Particles have …

5. Emission ...

6. The gain medium ...

7. Stimulated emission is …

8. An optical amplifier is …

9. A light beam or beam of light is ….

a) … a device that amplifies an optical signal directly, without the need to first convert it to an electrical signal.

b) … the process by which an atomic electron (or an excited molecular state) interacting with an electromagnetic wave of a certain frequency.

c) … an instantaneous amplitude and phase which vary randomly with respect to time and position.

d) … a narrow projection of light energy radiating from a source into a beam.

e) … is notable for its high degree of spatial and temporal coherence.

e) … is the process of supplying the energy required for the amplification is called.

f) … is a material with properties that allow it to amplify light by stimulated emission.

g) … can be spontaneous or stimulated.

h) … either absorbing or emitting photons.

7. Read the supplementary text, translate and entitle it:

Many scientific, military, medical and commercial laser applications have been developed since the invention of the laser in the 1958. The coherency, high monochromaticity, and ability to reach extremely high powers are all properties which allow for these specialized applications. In science, lasers are used in many ways, including: spectroscopy, atmospheric remote sensing, holographic techniques . Laser based LIght Detection And Ranging (LIDAR) technology has application in geology, seismology, remote sensing and atmospheric physics. Lasers have been used aboard spacecraft such as in the Cassini-Huygens mission. In astronomy, lasers have been used to create artificial laser guide stars, used as reference objects for adaptive optics telescopes.

Most types of laser are an inherently pure source of light; they emit near-monochromatic light with a very well defined range of wavelengths. By careful design of the laser components, the purity of the laser light (measured as the "linewidth") can be improved more than the purity of any other light source. This makes the laser a very useful source for spectroscopy.

8. Render the text: Laser

UNIT 2

Pre-text exercises:

1. Choose the right word: Say, tell, speak, talk

1. Don't … him about our plans. 2. I waited for an answer, but she didn't … a word.

3. He … us that he was going to buy a new car. 4. Do you … English? 5. Mike, we need to … . 6. To … you the truth, I don't remember anything. 7. Did the director … at the conference? 8. Do you know how to … good-bye in Arabic?

2. Find the Ukrainian equivalents for the following English and word combinations:

a) electronic devices, to increase the value, outside your home, current weather conditions, the digital door lock, wireless cameras,

b) за межами вашого дому; безпровідні камери; цифровий дверний замок; електронні прилади; збільшити величину (важливість); поточні погодні умови.

3. Match two parts of word combinations:

1) rainfall …

2) … Door Locks

3) … Camera

4) Roomba … Cleaner

5) little …

6) battery-…

7) a weather …

8) security reasons

a) Wireless

b) guy

c) amounts

d) Vacuum

e) Digital

f) man

g) powered

4. Read the text and translate it: Electronic Devices for the home.

When people think about electronic devices for their home they may think of security systems or garage door openers, but there are several electronics devices that are perfect for any home.  Electronic devices are good for security reasons and they are also good for checking to see what the weather is.  Whether you invest in these electronic devices depends on how much you want to increase the value of your home.  Homebuyers will love seeing these electronic devices in a home they are about to purchase. 

Wireless Weather Station:  Having one of these electronic devices outside your home will allow you to keep an eye on all the weather conditions.  These electronic devices do more than just tell you the temperature, they also tell you the wind speed, rainfall amounts, humidity, and so much more.  After all, the weather man may know the current weather conditions at the weather station, but there’s no way for him to know the conditions at your house.  Install one of these electronic devices and you’ll always know the exact weather conditions at your home.

Digital Door Locks:  These electronic devices will keep your home safer, than a regular lock.  Thieves are great at picking locks and most have no trouble entering a home that is “secured” with traditional door locks.  Installing one of these electronic devices in your home means that people will need cards in order to enter your locked home.  The digital door lock is basically a card reader.  You will need to present your card to the digital door lock for the door to unlock. These electronic devices will add to the value of your home.  Homebuyers love to see secure homes, especially homes that are secured with new technology.

Wireless Camera Having these electronic devices around your home will allow you to keep an eye on what’s going on outside your home.  You can set these tiny cameras up so that they are viewable on any TV or computer inside your home.  Many wireless security cameras require at least one cable or wire for power; "wireless" refers to the transmission of video/audio. However, some wireless security cameras are battery-powered, making the cameras truly wireless from top to bottom.

Solar LED House Numbers:  Installing some of these electronic devices outside your home will allow all your friends and family to easy find your home in the dark.  Best of all, the pizza delivery guy will be able to easily spot your home as well.  These electronic devices use the solar power of the sun to light the LEDs when the sun goes down.  These electronic devices are really bright.  You can either attach them to the outside of your house or you can attach the electronic devices to your mailbox.

Roomba Vacuum Cleaner:  These electronic devices are so useful.  Having one of these electronic devices, means that you’ll never have to vacuum again, because this little robot will do it for you.  The Roomba seeks out dirt and goes all over the floor searching for it.  You will need to empty this little guy every now and then.  You can also buy versions that can be set to vacuum the floor every so often.  Every home should have one of these electronic devices.

Post-text exercises: