A discharge lamp emitting near (carrier frequency ) is modelled

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

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

Problem

A discharge lamp emitting near λ0=500 nm\lambda_0 = 500\ \mathrm{nm} (carrier frequency ν0=c/λ0\nu_0 = c/\lambda_0) is modelled, as in the random-wavetrain model, as a stream of independent wavetrains of random phase, whose lengths are exponentially distributed with mean τ0=3.0 ns\tau_0 = 3.0\ \mathrm{ns}. The lamp's time-averaged irradiance is I=2.0 mW cm−2I = 2.0\ \mathrm{mW\,cm^{-2}}. ((a)) Write down the self-coherence function Γ11(τ)\Gamma_{11}(\tau) predicted by this model. ((b)) Evaluate ∣Γ11(τ)∣|\Gamma_{11}(\tau)| at τ=1.5 ns\tau = 1.5\ \mathrm{ns} and at τ=6.0 ns\tau = 6.0\ \mathrm{ns}.

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