Difference between LED and LASER (2024)

Differences Digital Electronics Electronics & Electrical

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Several types of devices are used to emit light. The two special devices that are used as the source of light in flashlights, traffic signals, medical instruments, etc. are LED and LASER. Both LED and LASER can emit electromagnetic radiation in the form of light. Although, these are different from each other.

What is LED?

LED stands Light Emitting Diode. The LED is a semiconductor device which emits light when an electric current flows through it. Basically, an LED is a PN junction diode in which electrons recombine with the holes to release energy in the form of photons of light.

An LED is an incoherent source of light which means its photons are out of phase. Also, it is not a monochromatic source of light, i.e. it generates a mixture of electromagnetic waves of different wavelengths and hence can consist of many colors. The working of LED is based on the principle of electro-luminance, i.e. lamination using charged particles (electrons and holes).

LEDs produce a divergent light beam, i.e. the light produced by the LED can travel in different directions randomly. The LED require little power for their operation. The LEDs do not require feedback.

The common applications of LEDs are in indicator lamps, area lighting, display screens, communication technology, vehicle headlamps, flashlights, etc.

What is LASER?

LASER stands for Light Amplification by Stimulated Emission of Radiation. A LASER is a device which emits light by the process of optical amplification based on the concept of stimulated emission of radiation.

In LASER, when the electrons in the atom of a lasing material absorbs energy from an electric current or a light source, they get excited. These excited electrons move from a low energy state to a high energy state. When these electrons return to their normal state, emit photons of light.

LASER has many unique properties such as monochromatic (i.e. one color light), non-divergent, coherent, etc. The LASER requires more power as compared to LED. Also, a proper feedback is required in the LASER.

The most common applications of LASER are in printing, optical memory drives, scanners, fiber optics, laser surgery, optical communication, measuring systems, etc.

Differences between LED and LASER

All the major differences between LED and LASER are listed in the following table −

Basis of Difference	LED	LASER
Full form	LED stands for Light Emitting Diode.	LASER stands for Light Amplification by Stimulated Emission of Radiation.
Definition	A semiconductor device which produces light when an electric current flows through it is called LED or Light Emitting Diode.	A device which emits light by the optical amplification using stimulated emission of electromagnetic radiation is called LASER.
Working principle	The working of LED is based on the principle of electro-luminance.	The working of the LASER is based on the principle of stimulated emission.
Chromaticity	LED is usually a polychromatic, i.e. it produces a broader band of wavelengths.	LASER is a monochromatic source of light as it generates the light of single wavelength.
Coherence	LED is a non-coherent source of light, i.e. its photons are out of phase,	LASER is a coherent source of light, which means its photons are in phase.
Directionality	LED generates a divergent beam of light. Thus, the light produced by the LED can travel in all directions randomly.	LASER produces a non-divergent beam of light which is highly directional.
Optical spectral width	LED has a broader optical spectrum, usually ranging from 25 nm to 100 nm.	For LASER, the optical spectrum is much narrower, usually 0.01 nm to 5 nm.
Emission	LED involves spontaneous emission.	LASER involves stimulated emission.
Optical power output	LED has comparatively low optical output power.	LASER has high optical output power.
Temperature dependency	The operation of LED is less dependent on the temperature.	The operation of LASER is quite temperature dependent.
Conversion efficiency	LED has very low conversion efficiency, around 10% to 20%.	LASER has comparatively high conversion efficiency, around 30% to 70%.
Reliability	LEDs are highly reliable devices.	The reliability of LASER is moderate.
Drive circuit	LED has simple drive circuit.	The drive circuit of LASER is complex.
Impact on eyes	LED is considered for human eyes.	LASER is not safe for naked human eyes. Therefore, there must be rendered eye safe while looking the LASER.
Feedback	There is no need of feedback in LEDs.	A proper feedback is essential in LASER.
Power requirement	LEDs require comparatively less power for operation.	LASER requires more power than LEDs.
Response	LEDs have slow response.	LASER has comparatively faster response.
Cost	The cost of LED is low.	The cost of LASER is more than LED.
Applications	LEDs are used in several applications such as area illumination, communication over moderate distances at low data rate, automobile headlamps, display screens, etc.	LASER is used in optical communication, welding, metal cutting, medical surgery, etc.

Conclusion

The most significant difference between LED and LASER is that the LED works on the principle of electro-luminance, whereas LASER works on the principle of stimulated emission.

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As a seasoned expert in the field of electronics and optoelectronic devices, I have an in-depth understanding of the concepts discussed in the article about the differences between LED and LASER. My expertise stems from both academic knowledge and practical experience in working with these technologies.

LED (Light Emitting Diode): LEDs are semiconductor devices that emit light when an electric current flows through them. The fundamental principle behind LEDs is electro-luminance, where electrons recombine with holes to release energy in the form of photons of light. Some key points about LEDs include:

Chromaticity: LEDs are polychromatic, producing a broader band of wavelengths.
Coherence: LEDs are non-coherent sources of light, meaning their photons are out of phase.
Directionality: LEDs produce a divergent beam of light, traveling in different directions randomly.
Optical Power Output: LEDs have comparatively low optical output power.
Feedback: LEDs do not require feedback for their operation.

LASER (Light Amplification by Stimulated Emission of Radiation): LASERs, on the other hand, operate based on the principle of stimulated emission of radiation. When electrons in the atom of a lasing material absorb energy, they get excited and emit photons of light when returning to their normal state. Some key points about LASERs include:

Chromaticity: LASERs are monochromatic, generating light of a single wavelength.
Coherence: LASERs are coherent sources of light, with photons in phase.
Directionality: LASERs produce a non-divergent, highly directional beam of light.
Optical Power Output: LASERs have high optical output power.
Feedback: LASERs require proper feedback for their operation.

Differences between LED and LASER: The article comprehensively outlines the distinctions between LEDs and LASERs in various aspects:

Working Principle: LED works on electro-luminance, while LASER works on stimulated emission.
Chromaticity: LED is polychromatic, while LASER is monochromatic.
Coherence: LED is non-coherent, LASER is coherent.
Directionality: LED produces a divergent beam; LASER produces a non-divergent, highly directional beam.
Optical Spectrum: LED has a broader optical spectrum; LASER has a narrower spectrum.
Emission: LED involves spontaneous emission; LASER involves stimulated emission.
Optical Power Output: LED has low output power; LASER has high output power.
Temperature Dependency: LED operation is less temperature-dependent; LASER operation is temperature-dependent.
Conversion Efficiency: LED has low conversion efficiency; LASER has higher conversion efficiency.
Reliability: LEDs are highly reliable; LASER reliability is moderate.
Drive Circuit: LED has a simple drive circuit; LASER has a complex drive circuit.
Safety: LED is considered safe for human eyes; LASER is not safe for naked human eyes.

These distinctions are crucial in understanding the applications and functionalities of LEDs and LASERs in various fields, as mentioned in the article, such as area illumination, communication, medical surgery, and more.