A superluminescent diode has a Gaussian spectral line centred at nm with full width…

PHYSICS · Multi-part · Fermi University Physics · Mathematical Methods for Physics · Optics & Photonics · Coherence and statistical optics

What an Instrument Can See, Ch Temporal coherence: correlation, spectrum and the interferometer

Problem

A superluminescent diode has a Gaussian spectral line centred at λ0=1050\lambda_0 = 1050 nm with full width at half maximum Δλ=60\Delta\lambda = 60 nm. Take c=3.00×108 m s−1c = 3.00\times10^8\ \mathrm{m\,s^{-1}}. ((a)) Convert the wavelength bandwidth to a frequency bandwidth Δν\Delta\nu using Δν≈cΔλ/λ02\Delta\nu \approx c\Delta\lambda/\lambda_0^2. ((b)) Use the Gaussian coherence-time result to find τc\tau_c and hence the coherence length ℓc\ell_c in vacuum.

Browse the problem library