The document discusses CO2 lasers, which were developed in 1964 and are known for being high-power, efficient continuous wave lasers that emit infrared light. It explains the principle of operation, construction, workings, and various materials used in their design, including their role in industrial applications like cutting and welding, as well as medical procedures such as laser surgery. The document highlights the advantages of using CO2 lasers due to their ability to focus intense heat on small areas.

1. Bangalore
institute of
technology
Physics Seminar
Group 2
Dr G K Narasimhamurthy
(Department of Physics)

2. CO2 lasers
Presented By: 6. Sameeksha Billava
7. Samhita
8. Sandeep Anand
9. Sarah MG
10. Saurabh Singh
2

3. INTRODUCTION
Co2 lasers
• The CO2 laser was one of the earliest gas laser
invented by Kumar Patel of Bell Labs in 1964 is one of
the most useful lasers.
• Carbon dioxide gas lasers are the highest power
continuous wave lasers that are currently available.
They are also quite efficient, the ratio of output power

4. The co2 laser produces a beam of infrared light
i.e.. This laser is not visible with bare eyes, its
principle wavelength bands centering around
9.6 and 10.6 micron.

5. Principle OF CO2 LASERS
For the laser action two points are
important one is the population inversion
between the two levels and second
increased density of the incident
radiation.
Principle of a CO2 laser is transition
between vibrational states of the same
electronic state by achieving population
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6. CONSTRUCTION
The CO2 laser can be constructed to have continuous wave powers
between milliwatts and hundreds of kilowatts.
CO2 lasers operate in the infrared, special materials are necessary for
their construction. Typically, the mirrors are silvers, while windows
and lenses are made of either germanium or zinc selenide. For high
power applications, gold mirrors and zinc selenide windows and lenses
are preferred. There are also diamond windows and lenses in use.
Diamond windows are extremely expensive, but their high thermal
conductivity and hardness make them useful in high-power
applications and in dirty environments. Optical elements made of
diamond can even be sand blasted without losing their optical
properties. Historically, lenses and windows were made out of salt.
While the material was inexpensive, the lenses and windows degraded
slowly with exposure to atmospheric moisture. 6

7. . 7

8. Working of CO2 Laser
• The vibrational and rotational modes of the CO2 can't be excited
themselves by photons i.e. by optical pumping.
• When a voltage is placed across the gas, electrons
collide with the N2 molecules and excite them to their levels.
• These of the asymmetric vibrational states in the CO2 molecules
vibrational levels happen to be at an energy very close to the
energy . Now the excited N2 molecule populates the asymmetric
vibrational states in the CO2 molecules through collisions.
8

9. Laser Structure and
Discharge Mechanism
 It consist of discharge tube of size 2.5cm in diameter and
5.0cm in length. Two optically plane and parallel mirrors,
one is completely reflector and another is partially
reflector.
 The discharge is filled with a mixture of CO2, N2 and He
gases at a pressure of few mm of mercury.
 A high value of DC voltage is used for electric discharge in
the tube due to which CO2 molecules breaks into CO & O
so periodic replacement of gas is required, O2 can corrode
the electrodes.

10. .
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11. APPLICATIONS
The advantage of using a laser for these applications is that
very intense heating source can be applied to a very small
area.
Because of the high power CO2 laser are frequently
used in industrial applications for cutting and
welding.
They are also very useful in surgical procedures because
water absorbs this frequency of light very well.
Some examples of medical uses are laser surgery, skin
resurfacing.

12. Thank
you