1. Prince kumar
kushwaha
0902ec101053
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5. The word 'photonics' is derived from the Greek word
"photos" meaning light; it appeared in the late 1960s
to describe a research field whose goal was to use
light to perform functions, that traditionally fell
within the typical domain of electronics, such as
telecommunications, information processing, etc.
Photonics as a field began with the invention of the
laser in 1960. Other developments followed:
including the laser diode in the 1970s, and optical
fibers for transmitting information. These inventions
formed the basis for the telecommunications
revolution of the late 20th century and provided the
infrastructure for the Internet
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7. Classical optics
Photonics is closely related to optics. However optics preceded the
discovery that light is quantized (when Albert Einstein explained the
photoelectric effect in 1905). Optics tools include the refracting
lens, the reflecting mirror, and various optical components known prior
to 1900.
Emerging fields
Photonics also relates to the emerging science of quantum information
in those cases where it employs photonic methods. Other emerging
fields include opto-atomics, in which devices integrate both photonic
and atomic devices for applications such as precision
timekeeping, navigation, and metrology(study of measurement);
polaritonics, which differs from photonics in that the fundamental
information carrier is a polariton, which is a mixture of photons and
phonons, and operates in the range of frequencies from 300 gigahertz
to approximately 10 terahertz. 9/24/2013 7

8. Photonics is related to quantum optics, optomechanics, electro-
optics, optoelectronics and quantum electronics. However each area
has slightly different meaning by scientific and government
communities and in the marketplace. Quantum optics often imply
fundamental research, whereas photonics is used to imply applied
research and development.
The term photonics more specifically imply :
*The particle properties of light,
*The potential of creating signal processing device technologies
using photons,and
*The practical application of optics.
The term optoelectronics imply devices or circuits that comprise
both electrical and optical functions, i.e., a thin-film semiconductor
device. The term electro-optics came into earlier use and specifically
encompasses nonlinear electrical-optical interactions applied.
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9. 1) Uninhibited light travels thousands of times faster than
electrons in computer chips. Optical computers will compute
thousand of times faster than any electronic computer can ever
achieve due to the physical limitation differences between light
and electricity.
2) Can packed more wavelengths (that is information channels)
into a optical fibre so that the transmission bandwidth is
increased than conventional copper wires.
3) Light encounters no electromagnetic interference than that of
electron in copper wires.
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10.  Biological Researcher and Technician
◦ uses microscopes with video camera attachment .
 Civil Engineer
◦ uses a laser beam with a theodelite to create a straight line over
long distances to measure the angle of a proposed road bridge
from a reference position.
 Auto focus camera lens designer
◦ uses computer programs to design the lens, the sensors and
electronics to measure the sharpness of the image to control the
focus, and CAD (Computer Aided Design) to design the
components and housings.
 Heating Engineer
◦ uses a Thermal Imaging camera to give a high quality picture
showing the temperature distribution across a scene.
 Communications System Installer
◦ couples optical fibers to electronic systems to route the
information between computers, monitors etc. or to control a
production machine.
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11.  Conservation Specialist
◦ uses laser beams to blast away the grime that has built up on
buildings and statues
 Environmental Inspector
◦ uses a laser beam projected into the smoke plume from a factory
to monitor the levels of the different gases emitted .
 Quality Control Inspector
◦ uses apparatus which measures the precise color spectrum of the
food product .
 Surgeon
◦ uses a slip-on device over the patients thumb which monitors an
infra-red beam to continuously measure the pulse rate. Also
inserts a fiber optic endoscope into the patient with a camera
attached.
 Skilled Machinist
◦ uses various types of laser beam under computer control
e.g. to cut holes finer than a human hair,
treat or decorate the metal surface,
join components together in a vacuum
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12. Applications of photonics are
ubiquitous. Included are all
areas from everyday life to the
most advanced science, e.g.
light detection,
telecommunications,
information processing,
lighting, metrology,
spectroscopy, holography,
medicine, military technology,
laser material processing, visual
art, biophotonics, agriculture,
and robotics.
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13. 1. Light sources
Light sources used in photonics are usually more sophisticated than
light bulbs. Photonics commonly uses semiconductor light sources like
light-emitting diodes (LEDs), superluminescent diodes, and lasers.
Other light sources include fluorescent lamps, cathode ray tubes
(CRTs), and plasma screens. Note that while CRTs, plasma screens, and
organic light-emitting diode displays generate their own light, liquid
crystal displays (LCDs) like TFT screens require a backlight of either cold
cathode fluorescent lamps or, more often today, LEDs.
Characteristic for research on semiconductor light sources is the
frequent use of III-V semiconductors instead of the classical
semiconductors like silicon and germanium. This is due to the special
properties of III-V semiconductors that allow for the implementation of
light emitting devices. Examples for material systems used are gallium
arsenide (GaAs) and aluminium gallium arsenide (AlGaAs) or other
compound semiconductors. They are also used in conjunction with
silicon to produce hybrid silicon lasers
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