The document discusses quantum dot lasers, which are semiconductor lasers utilizing quantum dots as the active medium for light emission. It covers various aspects including construction, working principles, applications in fields like healthcare and telecommunications, and their characteristics, advantages, and disadvantages. The presentation concludes that quantum dot lasers offer improvements in performance through enhanced characteristics such as low threshold current and high temperature stability, although they are challenging to manufacture.

1. Quantum dot laser
Presenter Sher khan
Department of Electronics

2. Content
Introduction
Construction
Working
QD Laser vs Normal Laser
Market Demand
Application
Characteristics
Advantages
Disadvantages
Conclusion
Summary

3. Introduction
• A quantum dot laser is a semiconductor laser that uses quantum
dots as the active laser medium in its light emitting region.
Quantum dots
semiconductor particles a few nanometers in size, having optical and
electronic properties
• Man-made crystals that have ability to convert a spectrum of light
into different colors
• They are so small that they are sometimes called zero-dimensional
or artificial atoms.

4. Construction

5. Working

6. QD laser vs Normal laser

7. Market demand
• Display, Medical Devices, Solar Cells, Photodetector/ Sensors, Lasers, Lighting (LED),
Batteries and Energy Storage, and Transistors
• Datacom network
• Telecom Network
• Optics
QD LASERS
Telecom
Network
Data
Network
Optics

8. Applications
Quantum dot lasers are used in
• healthcare
• Barcode readers
• Printing industry
• Fiber optical communication
• high resolution television

9. Characteristics
• Low threshold current
• Temperature stability
• Carrier diffusion
• bandgap absorption

10. Advantages
• High temperature stability
• Large modulation bandwidth
• Suppressed diffusion of non-equilibrium carriers to Reduced leakage
• Broad spectrum
• Gain is larger
• It is efficient laser

11. Disadvantages
• Difficult to manufacture
• very difficult to form high quality dot because of uniform size and
higher density

12. Conclusion
Semiconductor lasers with the quantum dot gain medium have been
studied to improve the laser characteristics including low threshold
currents density and high characteristic temperature. Surface density of
QD's has a great effect on the performance. It leads to increasing the
amount of radiation and hence increases the efficiency of the system.
The effect of surface density on the gain, threshold current and
characteristic temperature has been indicated.

13. Summary
In this presentation we discussed about quantum dot laser
Quantum dot laser is a semiconductor laser that use the quantum dots
as an active laser medium in its light emitting region
In quantum dot laser that the confinement in all three directions here
the quantum dot play the role of active atoms
By the varying of width and length of quantum dot laser
We can get the particular wavelength of laser light