User Account

All Pages

Population inversion, Physics

Assignment Help:
population inversion
  • The process in which the number of electrons (N2) in a higher energy state called ‘metastable state of an active medium is increased to a value greater than the number of electrons (N1) in the ground state (i.e.N2 > N1) is called population inversion.
  • There are certain special substances or systems in which the electrons, once excited can remain in the higher energy state for longer times.
  • Such systems are called Active systems or Active Media.
  • Active systems are generally compounds or mixtures of different elements.
  • Consider three electronic states 1,2,3, in an active medium. (Refer text book for diagram.
  • Normally Large number of electrons exist in the Lowest energy state called ground state.
  • Let this number be N1 when photons of energy equal to the difference between E3 and E1 are incident, the electrons from state (1) are excited to state (3) because of absorption. But the property of the state (3) is such that the life time of electrons
  • in the state is very short, of the order 10-8 seconds. 
  • Of course most electrons return to state (1) from state (3) by spontaneous emission, but some electrons go to state (2) also.
  • Therefore, the electrons from the state (3) undergo a quick transition to the state (2) by emitting only a small energy (E3 - E2) which is simply absorbed as the thermal energy by the medium itself.

Related Discussions:- Population inversion

Measure wavelength of light used in newton''s ring experiment, Q. How shall...

Q. How shall you measure wavelength of light used in Newton's ring experiment? Derive the formula used.   Measurement of Wavelength of Monochromatic Light using Newton’s Ri

Work and energy, how can u call off the potential energy of an object when ...

how can u call off the potential energy of an object when the world is full of refrences and the world itself is relative? what would be the potential energy for a object lying in

Measuring field strength of permanent magnets, I want to measure H, not B T...

I want to measure H, not B The magnets in question are permanent magnets (large Neo or SmCo magnets), not coils =====================....Steel ____........................____ |.

Production of pure spectrum, how do you produce a pure spectrum

how do you produce a pure spectrum

How are extrinsic fiber optic sensors used, How are extrinsic fiber optic s...

How are extrinsic fiber optic sensors used? Extrinsic fiber optic sensors give best protection of measurement signals against noise corruption. Unluckily, several conventional

Scanning, Scanning is process of dividing an image on the screen into a lar...

Scanning is process of dividing an image on the screen into a large number of very small squares formed by sets of horizontal and vertical straight lines.   Iconoscope i

Cirucular force, If 3 particles of different mass located at different pos...

If 3 particles of different mass located at different positions: 1- 1kg position : (0,0) 2- 2kg position: (0,5) 3- 3kg position : (-1,0) If a force of 2 N at 45 degrees is applie

Special features and applications of carbon dioxide laser, What are the Spe...

What are the Special features and Applications of carbon dioxide laser? Special features and Applications of carbon dioxide laser: The efficiency of this Laser is extremely

Determine the refractive index of a pair of media, Determine the refractive...

Determine the refractive index of a pair of media provided critical angle as 40°. Determine the angle of deviation generated by a thin prism of refracting angle 5° and refractiv

Define angular momentum, The turning movement of a particle about the axis ...

The turning movement of a particle about the axis of rotation is called the angular momentum of the particle and is measured as the product of the linear momentum and the perpendic

Write Your Message!

Captcha
Order Assignment

Featured Services

Order Now

Popular Subjects

Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

Submit Assignment

Academics

Major Subjects

Majors

Get In Touch

whatsapp: +91-977-207-8620

Phone: +91-977-207-8620

Email: [email protected]

TERMS & POLICIES

HELP & SUPPORT

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd