An analytical expression for focal intensity is derived for arbitrary surface profiles and arbitrary groove patterns of compressor gratings.The expression is valid for different compressor designs:plane and out-of-pla...An analytical expression for focal intensity is derived for arbitrary surface profiles and arbitrary groove patterns of compressor gratings.The expression is valid for different compressor designs:plane and out-of-plane compressors,symmetric and asymmetric compressors(compressors composed by two not-identical pairs of gratings)and a twograting compressor.It is shown that the quality requirements for the optics used to write a grating are higher than for the grating.The focal intensity can be maximized by rotating each grating around its normal by 180 degrees.Moreover,it may be increased to maximum by interchanging any two gratings in the compressor,because imperfections of an individual grating do not additively affect the focal intensity.The intensity decrease is proportional to the squared pulse spectrum width and the squared total distortions of the second and third gratings of the four-grating compressor and the total distortions of two gratings of the two-grating compressor.展开更多
The impact of compressor gratings and transport optics imperfections on the power contrast ratio(PCR) is considered analytically,taking into account diffraction and all dispersion orders.All types of imperfections,inc...The impact of compressor gratings and transport optics imperfections on the power contrast ratio(PCR) is considered analytically,taking into account diffraction and all dispersion orders.All types of imperfections,including surface roughness,reflectivity fluctuations and surface dirt/damage/obscuration as well as the roughness and obscuration on the optics used to write holographic gratings are allowed for.For the same roughness and obscuration,the contribution to the PCR of the latter is significantly greater than the contribution of the gratings.Comparison of the PCR caused by obscuration and by roughness showed that at short times the latter prevails,whereas at long times the obscuration is dominant.The radiation scattered by the second and third gratings arrives at the target before the main pulse in the form of a vertical strip near the beam axis.Then this strip moves uniformly towards the axis,reaching it simultaneously with the main pulse.展开更多
文摘An analytical expression for focal intensity is derived for arbitrary surface profiles and arbitrary groove patterns of compressor gratings.The expression is valid for different compressor designs:plane and out-of-plane compressors,symmetric and asymmetric compressors(compressors composed by two not-identical pairs of gratings)and a twograting compressor.It is shown that the quality requirements for the optics used to write a grating are higher than for the grating.The focal intensity can be maximized by rotating each grating around its normal by 180 degrees.Moreover,it may be increased to maximum by interchanging any two gratings in the compressor,because imperfections of an individual grating do not additively affect the focal intensity.The intensity decrease is proportional to the squared pulse spectrum width and the squared total distortions of the second and third gratings of the four-grating compressor and the total distortions of two gratings of the two-grating compressor.
基金supported by the Ministry of Science and Higher Education of the Russian Federation (Project No. FFUF-2025-0011)
文摘The impact of compressor gratings and transport optics imperfections on the power contrast ratio(PCR) is considered analytically,taking into account diffraction and all dispersion orders.All types of imperfections,including surface roughness,reflectivity fluctuations and surface dirt/damage/obscuration as well as the roughness and obscuration on the optics used to write holographic gratings are allowed for.For the same roughness and obscuration,the contribution to the PCR of the latter is significantly greater than the contribution of the gratings.Comparison of the PCR caused by obscuration and by roughness showed that at short times the latter prevails,whereas at long times the obscuration is dominant.The radiation scattered by the second and third gratings arrives at the target before the main pulse in the form of a vertical strip near the beam axis.Then this strip moves uniformly towards the axis,reaching it simultaneously with the main pulse.
