When the refractive index $$\mu $$ of the active medium changes by $${\Delta \mu }$$ in a laser resonator of length L, the change in the spectral spacing between the longitudinal modes of the laser is (c is the speed of light in free space)
A. $$\frac{c}{{2\left( {\mu + \Delta \mu } \right)L}}$$
B. $$\frac{c}{{2\Delta \mu L}}$$
C. $$\frac{c}{{2L}}\frac{{\Delta \mu }}{{\mu \left( {\mu + \Delta \mu } \right)}}$$
D. zero
Answer: Option C
This Question Belongs to Engineering Physics >> Atomic And Molecular Physics
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