Resonance frequency — UPSC Physics Optional CSE 2025 Paper I

For a \text{He}-\text{Ne} laser system, what will be the magnitude of \Delta\omega_D which represents FWHM of the line shape function g(\omega), if resonant frequency \omega_0 = 3 \times 10^{15}\text{ s}^{-1} and temperature T = 300\text{ K}?