Four-level laser

Tested in 3 real MPSC questions across 1 year (2014–2014). See it in context on the interactive Concept Graph →

Years it was asked

2014

What you need to know first

Laser principlesEnergy levels

Real questions that test this

त्रिस्तरीय लेझर मध्ये, अंशस्थिर अवस्था ______ मध्ये स्थिर असते. / In a three level laser, the metastable state is situated :

a)निम्नतम अवस्थेच्या खाली / below ground state

b)उत्तेजित स्थितीच्या वर / above excited state

c)उत्तेजित आणि निम्नतम स्थितीच्या मध्ये / in between excited and ground state&check; Correct

d)ऐन निम्नतम स्थितीत / exactly at ground state

In a three-level laser system, the metastable state is located between the upper excited state and the lower ground state.

पंपण प्रक्रीयेचे कमीत कमी प्रमाण ______ मध्ये आवश्यक असते : / Lesser amount of pumping is required in :

a)चतुःस्तरीय लेझर / four level laser&check; Correct

b)त्रिस्तरीय लेझर / three level laser

c)द्विस्तरीय लेझर / two level laser

d)पर्याय क्रमांक (1) आणि (2) / both (1) and (2) require equal pumping

A four-level laser requires a lesser amount of pumping compared to a three-level laser because the lower laser level is above the ground state, emptying rapidly.

प्रेरित उत्सर्जन प्रक्रियेसाठी त्रिस्तरीय लेझर मध्ये ______ . / For induced emission in a three level laser :

a)50% अणू अंशस्थिर स्थितीत असतात. / 50% of atoms should be in metastable state.

b)50% पेक्षा कमी अणू अंशस्थिर स्थितीत असतात. / < (less than) 50% of atoms should be in metastable state

c)50% पेक्षा जास्त अणू अंशस्थिर स्थितीत असतात. / > (more than) 50% of atoms should be in metastable state&check; Correct

d)अंशस्थिर स्थिती रिक्त असते. / metastable state must be vacant

In a three-level laser system, population inversion requires more than 50% of the atoms to be pumped into the metastable state so that stimulated emission can dominate over absorption.

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