In a Ruby laser, what mechanism achieves the population inversion required for stimulated emission of coherent optical radiation?
Answer and explanation
Correct answer: B. Optical pumping using an intense xenon flash lamp
- Step 1: A ruby laser uses a synthetic sapphire crystal doped with chromium ions (Cr3+). Step 2. Optical pumping from a xenon flashtube excites ground-state chromium ions into broad absorption bands. Step 3. Rapid radiationless decay transfers electrons to a metastable level, establishing population inversion relative to the ground state. Answer: Optical pumping using an intense xenon flash lamp. Why not the others: Electrical discharge is used in He-Ne lasers; forward-bias injection in semiconductor diode lasers.
Practise more Atomic, Nuclear and Quantum Physics.
Free questions with an explanation for every one, and full timed ECAT Pakistan mock tests.
More Atomic, Nuclear and Quantum Physics questions
- In Compton scattering, what is the maximum possible wavelength shift (Compton shift delta lambda) when a photon collides with a free station…
- What is the energy required to excite an electron in a hydrogen atom from its ground state (n = 1) to the first excited state (n = 2)?
- According to Heisenberg's uncertainty principle, if the position of an electron is determined with an uncertainty of delta x = 1.0 x 10^-10…
- In a nuclear fusion reaction, four protons fuse to form a helium-4 nucleus with a mass defect of delta m = 0.0287 atomic mass units (u). How…
- What is the velocity of an electron whose de Broglie wavelength is equal to its Compton wavelength (lambda_c = h / (m_e * c))?
- What nuclear particle is emitted when cobalt-60 (Z = 27, A = 60) decays into nickel-60 (Z = 28, A = 60)?