Optical frequency doubler using quantum well semiconductor structures
AssigneeThomson-CSF
InventorsDominique Delacourt, Jean-Claude Pocholle, Michel Papuchon
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Abstract
Disclosed is a frequency doubler having a quantum well semiconductor structure and a second-order non-linear susceptibility grating that can be used to amplify notably the frequency doubling. The grating can be recorded optically or electrically within the semiconductor structure and has a pitch in the plane of the structure. Such a frequency doubler finds particular application to optical recording or reading systems.
Claims12
An electromagnetic wave frequency doubler, the electromagnetic wave having a wavelength .lambda.w, with a semiconductor structure comprising a stack of layers constituted by semiconductor materials enabling the creation of potential wells, wherein there are at least two discrete energy levels e.sub.1 and e.sub.2 in the wells such that e.sub.1 is smaller than e.sub.2, the density of probability of the presence of electrons on e.sub.2 is an asymmetrical function and said doubler comprises a second-order non-linear susceptibility grating resulting from the populating, with electrons, of the level e.sub.1 and from this asymmetry, the pitch of the grating being in the plane of the layers, said grating being optically controllable by an optical beam with a wavelength .lambda.p that locally and periodically irradiates the semiconductor structure so as to locally populate the energy level e.sub.1 with electrons and said grating making it possible to carry out the phase matching between the polarization created by an incident electromagnetic wave and a created harmonic wave, the two waves getting propagated in the plane of the stack of layers.
An electromagnetic wave frequency doubler, the electromagnetic wave having a wavelength .lambda.w, comprising:
- a stack of layers formed of semiconductor materials for forming potential wells, wherein there is at least two discrete energy levels e.sub.1 and e.sub.2 in the potential wells such that e.sub.1 is smaller than e.sub.2, and a density of probability of a presence of electrons on e.sub.2 is an asymmetrical function;
- a second-order non-linear susceptibility grating resulting from populating, with electrons, of the level e.sub.1 and from the asymmetrical function, a pitch of the grating being in a plane of the stack of layers, said grating being optically controllable by an optical beam with a wavelength .lambda.p that locally and periodically irradiates the stack of layers so as to locally populate the energy level e.sub.1 with electrons and said grating providing phase matching between a polarization created by an incident electromagnetic wave and a created harmonic wave, these two waves being propagated in the plane of the stack of layers.
Dependencies are inferred from the claim text.