Advantages of Semiconductor Laser | disadvantages of Semiconductor Laser
This page covers advantages and disadvantages of Semiconductor Laser. It mentions Semiconductor Laser advantages or benefits and Semiconductor Laser disadvantages or drawbacks.
What is Semiconductor Laser?
• Lasers are devices which produce intense beams of light which are monochromatic, coherent and highly collimated. Light can travel over great distances or can be focused to very small spot with brightness higher than the sun. We are aware that Laser is acronym for "Light Amplification by Stimulated Emission of Radiation".
• Semiconductor lasers are compact in size as they are made using semiconductor materials on nanometer scale accuracy.
• It is similar to transistor and has operation like LED, but the output beam has characteristics of laser light.
• The material most often used in semiconductor laser is GaAs (Gallium Arsenide). Hence it is known as gallium arsenide laser. It is also called as injection laser.
• The figure-1 depicts simple semiconductor p-n junction structure known as homojunction laser diode.
• In semiconductor laser diode, optical gain is produced in semiconductor material. The recombination of injected holes and electrons (and consequent emission of photons) in a forward biased semiconductor p-n junction represents direct conversion of electricity to light.
• The multiple reflections of emitted radiation within the optical cavity region helps to build up photons for sustainable stimulated emission from the junction laser diode. If rate of stimulated emission is made significantly higher compare to loss rate, then the device turns to the lasing state. This situation is known as gain state of the system.
• Based on their construction and materials used, Semiconductor laser types include simple homojunction laser diode, DH (Double Heterojunction) laser, QW (Quantum Well) laser, DFB ( Distributed Feedback ) laser, Tunable laser, Surface emitting laser etc.
• Based on types of laser, it is used in various applications such as storing information in CDs and DVDs, high speed transmission of information over fiber optic cable, welding, surgery, military, holography etc.
• Semiconductor laser can be pulsed at varying rate and pulse widths. Hence it is used as natural transmitter of digital data.
Benefits or advantages of Semiconductor Laser
Following are the benefits or advantages of Semiconductor Laser:
➨It employs passive cooling technique in its design.
➨It cosumes less power.
➨It is very efficient. It offers excellent efficiency with very high operation duration.
➨It is very easy in operation.
➨Semiconductor lasers are cheap and economical to afford.
➨It offers long life, highly monochromatic, tunable and continuous beam.
➨It is simple in design/construction and compact in size. Mirrors are not required unlike other laser types.
Drawbacks or disadvantages of Semiconductor Laser
Following are the drawbacks or disadvantages of Semiconductor Laser:
➨This laser is not suited for many applications due to its low power production.
➨The temperature affects its output.
➨The output beam profile has unusual shape due to lasing medium's too short size and rectangular shape.
➨Beam divergence is much greater compare to other laser types.
➨Its cooling requirement is considered to be its drawback in some cases.