dorsal/arxiv
View SchemaExact Solution for the Second Harmonic Generation in XFELs
| Authors | Gianluca Geloni, Evgeni Saldin, Evgeni Schneidmiller, Mikhail Yurkov |
|---|---|
| Categories | |
| ArXiv ID | physics/0508046 |
| URL | https://arxiv.org/abs/physics/0508046 |
Abstract
The generation of harmonic radiation through a non-linear mechanism driven by bunching at fundamental frequency is an important option in the operation of high gain Free-Electron Lasers (FELs). The use of harmonic generation at a large scale facility may result in achieving shorter radiation wavelengths for the same electron beam energy. This paper describes a theory of second harmonic generation in planar undulators with particular attention to X-Ray FELs (XFELs). Our study is based on an exact analytical solution of Maxwell equations, derived with the help of the Green's function method. On the contrary, up-to-date theoretical understanding of the second harmonic generation is only limited to some estimation of the total radiation power based on the source part of the wave equation. Moreover, we find that such part of the wave equation is presented with several incorrect manipulations among which is the omission of an important contribution. Our work yields correct parametric dependencies and specific predictions of additional properties such as polarization, angular distribution of the radiation intensity and total power. The most surprising prediction is the presence of a vertically polarized part of the second harmonic radiation, whereas up-to-date understanding assumes that the field is horizontally polarized. Altogether, this paper presents the first correct theory of second harmonic generation for high gain FELs.
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"abstract": "The generation of harmonic radiation through a non-linear mechanism driven by\nbunching at fundamental frequency is an important option in the operation of\nhigh gain Free-Electron Lasers (FELs). The use of harmonic generation at a\nlarge scale facility may result in achieving shorter radiation wavelengths for\nthe same electron beam energy. This paper describes a theory of second harmonic\ngeneration in planar undulators with particular attention to X-Ray FELs\n(XFELs). Our study is based on an exact analytical solution of Maxwell\nequations, derived with the help of the Green\u0027s function method. On the\ncontrary, up-to-date theoretical understanding of the second harmonic\ngeneration is only limited to some estimation of the total radiation power\nbased on the source part of the wave equation. Moreover, we find that such part\nof the wave equation is presented with several incorrect manipulations among\nwhich is the omission of an important contribution. Our work yields correct\nparametric dependencies and specific predictions of additional properties such\nas polarization, angular distribution of the radiation intensity and total\npower. The most surprising prediction is the presence of a vertically polarized\npart of the second harmonic radiation, whereas up-to-date understanding assumes\nthat the field is horizontally polarized. Altogether, this paper presents the\nfirst correct theory of second harmonic generation for high gain FELs.",
"arxiv_id": "physics/0508046",
"authors": [
"Gianluca Geloni",
"Evgeni Saldin",
"Evgeni Schneidmiller",
"Mikhail Yurkov"
],
"categories": [
"physics.acc-ph",
"physics.optics"
],
"title": "Exact Solution for the Second Harmonic Generation in XFELs",
"url": "https://arxiv.org/abs/physics/0508046"
},
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