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Write the difference between LED and Laser diode

written 8.5 years ago by vermavarsha432 • 1.0k

modified 4.1 years ago by ninadsail • 10

advanced engineering physics

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written 8.5 years ago by vermavarsha432 • 1.0k

modified 5.0 years ago by yashbeer ★ 11k

LED	LASER
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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