Write the difference between LED and Laser diode
1 Answer
LED - Light emitting diode LASER - Light amplification by stimulated emission of radiation
It is polychromatic It is highly monochromatic
It is not coherent It is highly coherent
Spontaneous emission is responsible for it. Spontaneous emission is responsible for it.
Not directional Highly directional
Poor energy is associated Highly energetic
LED’s are small in size, longer life, reliable & require little power. Laser’s are bigger in size, longer life, less reliable & require more power than LED.
Generation of photon by spontaneous emission Generating photon by stimulated emission.
LED’s produce a divergent & incoherent light beam. Laser produces a monochromatic & coherent light beam.
Types of LED (a) surface emitter (b) Edge emitter Types of LASER (a) semiconductor Laser (b) Gas Laser
Their response is fast. Their response is faster than LED.
Bandwidth of LED is moderate Bandwidth of Laser is higher
Here require drive current is 50 to 100mA Here require drive current is Threshold current of 5-40mA.
Feedback is not required in LED. Proper feedback is essential in LASER to be treated as an optical source.
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