Apparatus and method for measuring the intensity and phase of a light pulse

摘要

Provided are a method and an apparatus for measuring the spectral intensity and phase of a light pulse having an arbitrary time duration. The apparatus includes: a nonlinear mixing means for generating a signal light pulse expressed by the following Formula (★ denotes an operator representing general nonlinear mixing, and α denotes a coefficient which is proportional to a nonlinear susceptibility in the nonlinear mixing) by nonlinearly mixing a reference light pulse having an electric field Er(t−τ) delayed by an optical delay means and a measurement target light pulse having an electric field E0(t); and
Er(t−τ)+αEr(t−τ)★E0(t)
an imaging spectrum device for spectrally splitting the signal light pulse and outputting a Fourier transform signal expressed by the following Formula (F denotes a symbol indicating Fourier transform, * denotes a complex conjugate, and R denotes a symbol indicating a real part),
|F[Er(t−τ)]|2+|αF[Er(t−τ)★E0(t)]|2+2R{αF[Er(t−τ)]*·F[Er(t−τ)★E0(t)]}.

主权项

1. An apparatus for measuring spectral intensity and an absolute value of spectral phase of a light pulse from a signal of a second term of a Fourier transform signal representing frequency resolved optical gate signal and a signal of a third term of said Fourier transform signal representing electro-optical sampling signal, said apparatus comprising:
a mirror for changing a time delay τ between a measurement target light pulse having an electric field E0(t) changing with a time t and a reference light pulse having an electric field Er(t); a nonlinear mixer for generating a signal light pulse expressed by a Formula Er(t−τ)+αE(t−τ)★E0(t), an operator ★ representing general nonlinear mixing, and α representing a coefficient that is proportional to a nonlinear susceptibility in the nonlinear mixing, by nonlinearly mixing said reference light pulse having an electric field Er(t−τ) delayed by said mirror and said measurement target light pulse; and a spectrometer for spectrally resolving said signal light pulse and outputting said Fourier transform signal, said Fourier transform signal expressed by a Formula |F[Er(t−τ)]|2+|αF[Er(t−τ)★E0(t)]2+2R{αF[Er(t−τ)]*·F[Er(t−τ)★E0(t)]}, F representing a symbol indicating Fourier transform, * representing a complex conjugate, and R representing a symbol indicating a real part.