Method and device for generating and adjusting circular polarization or elliptic polarization higher harmonic

Abstract

The invention discloses a method and a device for generating and adjusting a circular polarization or elliptic polarization higher harmonic. The method is characterized in that: two beams of linear polarized lights with different frequencies are utilized to drive a gas medium to radiate a higher harmonic, and the efficiency of radiating the higher harmonic is ensured through adjustment of a relative phase of a bicolor field; a polarization included angle and an intensity ratio of the bicolor field are adjusted, and the ellipsometry of the radiated higher harmonic is adjusted, so that the intensities of the radiated odd and even higher harmonics are obviously different under the proper polarization included angle and intensity ratio, and the odd and even higher harmonics have the same rotation property respectively and can be used for synthesizing high-efficiency circular polarization or elliptic polarization attosecond pulses. The method of the invention is a practical method for generating and adjusting a coherent extreme ultraviolet ellipsometry.

Description

technical field [0001] The present invention relates to the field of ultrafast laser technology, and more specifically, to a method and device for generating and adjusting high-order harmonics of circular or elliptical deviation. Background technique [0002] The generation and application of attosecond pulses is a new field that people are exploring. Research on attosecond coherent extreme ultraviolet light pulse synthesis technology based on high-order harmonics not only has great application value in the fields of atomic and intramolecular electronic motion and nuclear structure detection, but also has great application value in ultrafast information, material science and life science. The field will also create an unprecedented extreme experimental environment and provide unprecedented research conditions. [0003] In 2001, scientists synthesized an extreme ultraviolet pulse with a pulse width of 650 attoseconds for the first time through high-order harmonics (M. Hentsc...

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Problems solved by technology

The high-order harmonics radiated under the action of two-color circular polarization, although each of its high-order harmonics is circularly or elliptically polarized, but the handedness of the two adjacent high-order harmonics is opposite. Thus the synthesized attosecond pulse is still linearly polarized

The driving light used in the monochromatic non-collinear circularly polarized light technology is composed of two beams of circularly polarized light with a certain included angle in the propagation direction, opposite handedness and the same frequency. The intersection and overlapping area presents linear polarization, and the polarization direction changes continuously on the transverse section. It can radiate higher harmonics and produce circular polarization in the far-field diffraction superposition. However, the intersection and overlapping area of ​​two non-collinear lights is limited, so the radiation of higher harmonics is limited. low wave efficiency

[0005] For the circular or ellipsometric attosecond technology, the current problem is that in the existing methods for generating circular or ellipsometric high-order harmonics, either the different order high-order harmonics of the radiation exhibit anti-handedness, making the synthesized The attosecond pulse is still linearly polarized; or the high-order harmonic efficiency of the radiation is low, which limits the energy of the synthesized attosecond pulse, thus restricting the practical application and development of circular or elliptical attosecond pulses

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