Abhishek  Verma, Vikesh  Gupta, 
    Analysis of Three Frequency Undulator Intensity and Gain Due to off Axis Contribution in Free Electron Laser,
    Research Journal of Applied Sciences,
    Volume 9,Issue 6,
    2014,
    Pages 329-335,
    ISSN 1815-932x,
    rjasci.2014.329.335,
    (https://makhillpublications.co/view-article.php?doi=rjasci.2014.329.335)
    Abstract: In this study, researchers study the three frequency undulator radiation and free electron laser gain for higher harmonics with the inclusion of off axis contribution. When electron enters the field off axis it causes additional oscillations due to which intensity and gain reduction take place. To enhance the intensity and gain, researchers introduce a new scheme, i.e., the three frequency undulator scheme.
    Keywords: Free electron laser;undulator;scheme;gain;axis