– Laser is a very popular device since last few years.
– Emission of light beam is purpose of this device.
– It does this through a process based on the “stimulated emission of the electromagnetic radiation” known as the optical amplification.
– This is why the device has got the name LASER which stands for “light amplification by the stimulated emission of radiation”.
How do lasers differ from the various other light sources?
– The lasers produce the beam of light in a coherent way that distinguishes it from the other sources of light.
– It is because of this spatial coherence property that the laser can be focused even up on a spot that is tight enough.
– Laser has paved way for applications such as the laser lithography and the laser cutting.
– This property of spatial coherence is also responsible for keeping a laser beam collimated over distances that are long enough.
– This in turn permits the working of the laser pointers.
– Another property of the laser is its temporal coherence.
– It is by the virtue of this property that the laser is able to have quite a narrow spectrum.
– By narrow spectrum we mean, that a laser can emit light of only one color.
– Also, this property helps it in emitting pulses of light of extremely short duration i.e., of a femtosecond.
Use of LASER
– Today there are a number of applications for lasers such as:
- In consumer devices including barcode scanners, DVD players, laser printers and so on.
- Medicinal applications such as in laser surgery and a number of other skin treatments.
- In cutting and welding of materials.
- In military and law enforcement devices like for measuring range and speed of the weapons and marking the targets.
- In laser lighting displays. These displays make use of the laser light for entertaining.
- In scientific researches.
– Very high irradiance can be achieved by focusing the laser beams at tight spots.
– Their power can be concentrated at a point situated at a large distance by launching beams having very low divergence.
– There are lasers called the single wavelength lasers that do not generate radiation in a single polarization but they do so in several different modes where for each mode there is a different frequency.
– This also points to monochromatic property of the laser beams.
– Today lasers that can emit a broad spectrum of light have been invented.
– Lasers offer a promising future for the wireless transmissions but with that come several safety concerns.
– Nowadays, in telecommunications low power lasers are more prominent.
– Surgeries, cutting and welding involve high power lasers.
– Lasers are new in the field of wireless transmission, space exploration and propulsion.
– Interference of the microwaves with the communication system of the satellites is a major issue in case of the solar power systems that make use of the microwave power transmission.
– These communication systems make use of the frequencies lying in the multi – gigahertz range that is the most appropriate range for the microwave power transmission.
– However, this issue is not found in the laser wireless transmission since there is no interference.
– This is so because there is a great disparity in the frequencies of the satellite communications bands and lasers.
– Another reason is that there are no significant side lobes present in the narrow laser beams which are known to introduce interference.
– Laser beams also get attenuated by the atmosphere of the Earth and its weather conditions.
– Scattering causes highest attenuation when there is less difference between the size of the particles and wavelength of the laser light.
– Since the wavelength of the laser is very small when compared to the microwave beams it undergoes more severe attenuation.
– This occurs to such an extent that the power beam interruptions will start occurring.