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A technique for correcting wave front aberrations in large optical telescopes by four wave mixing processes which allow near-diffraction limited performance in the presence of relatively large physical distortions which could be present in low cost lightweight primary mirrors of desired high resolut

A technique for correcting wave front aberrations in large optical telescopes by four wave mixing processes which allow near-diffraction limited performance in the presence of relatively large physical distortions which could be present in low cost lightweight primary mirrors of desired high resolution imaging instruments. A local source reference beam, which is used to sample the aberrations in the telescope optical train, is mixed with the incoming image beam, which can be filtered and can be at a slightly different wavelength than the aberrated reference beam; a corrected image wave front is then extracted and brought to a focus and recorded as the desired high resolution image. A non-linear optical material is the medium used to permit either degenerate or non-degenerate four wave mixing processes to occur, with the aberrated reference beam as the pump wave which in effect subtracts the instrument wave front aberrations from the incoming image beam, thereby producing a high resolution image free from the aberrations present in the instrument optics. This technique allows the construction of very large optical elements in an inexpensive fashion, since surface tolerances can be relaxed greatly due to the phase correction process in the non-linear optical mixing media. The use of appropriate non-linear media for microwave and millimeter wave spectral regions allow these techniques to be applied to correct aberrations in large radar antennas. This could result in inexpensive, space-based millimeter wave imaging systems.

대표청구항 ▼

An aberration correction imaging device, in which an object beam of electromagnetic radiation and an aberration-sampling reference beam both make a single pass through the aberrations present in said device and interact with an unaberrated reference beam in a phase conjugating medium, producing as o

An aberration correction imaging device, in which an object beam of electromagnetic radiation and an aberration-sampling reference beam both make a single pass through the aberrations present in said device and interact with an unaberrated reference beam in a phase conjugating medium, producing as output an unaberrated image beam, said device comprising: said phase conjugating medium; means for producing reference beams; means for receiving the incident object beam and the aberration-sampling reference beam onto optical components having aberrations; means for directing the resulting aberrated object beam, the aberration-sampling reference beam and the unaberrated reference beam onto said phase conjugating medium to thereby produce the output unaberrated image beam, and means for separating the unaberrated image beam from the aberration-sampling reference beam and the unaberrated reference beam, said means for separating utilizing differences in angular direction, polarization, or wavelength between the unaberrated output image beam from the reference beams.