Abstract. Methods for the spatio-temporal shaping of photo- cathode laser pulses for generating high brightness electron beams in modern linear accelerators are discussed. The possibi- lity of forming triangular laser pulses and quasi-ellipsoidal structures is analyzed. The proposed setup for generating shaped laser pulses was realised at the Institute of Applied Physics (IAP) of the Russian Academy of Sciences (RAS). Currently, a prototype of the pulse-shaping laser system is installed at the Photo Injector Test facility at DESY, Zeuthen site (PITZ). Preliminary experiments on electron beam genera- tion using ultraviolet laser pulses from this system were carried out at PITZ, in which electron bunches with a 0.5-nC charge and a transverse normalized emittance of 1.1 mm mrad were obtained. A new scheme for the three-dimensional shaping of laser beams using a volume Bragg profiled grating is proposed at IAP RAS and is currently being tested for further electron beam generation experiments at the PITZ photoinjector. Keywords: 3D-shaping of laser pulses, photoinjector, linear electron accelerator, generation and acceleration of electron beams, normal- ized transverse emittance 1. Introduction Currently, one of the most important fields utilizing methods for three-dimensional laser pulse shaping is related to electron photoinjector physics. Here, laser pulses are employed to illuminate a photocathode surface in order to generate electron bunches resulted from a photoeffect. The cathode is placed in a vacuum chamber inside a microwave cavity. The laser pulse repetition rate is a subharmonic of a microwave field, which allows generating synchronized with the micro- wave device laser pulses and efficiently accelerating generated electron bunches. It is well known that the intensity distribution of laser pulses determines the electron beam parameters, such as the spatial distribution of the charge, the value of the transverse normalized emittance, and others. By controling the spatio± temporal distribution of the laser pulse intensity one can change the electron bunch parameters. The required electron beam characteristics are defined by the specific tasks for which they are generated. One of the most promising applications is the develop- ment of free-electron lasers (FELs) operating in the single- pass self-amplified spontaneous emission (SASE) mode. In this case, electron bunches should satisfy strict requirements for the peak brightness and stability, so one needs to generate very short electron bunches with high current (on the order of S Yu Mironov, A V Andrianov, E I Gacheva, V V Zelenogorskii, A K Potemkin, E A Khazanov Institute of Applied Physics, Russian Academy of Sciences, ul. Ul'yanova 46, 603950 Nizhny Novgorod, Russian Federation P Boonpornprasert, M Gross, J Good, I Isaev, D Kalantaryan, M Krasilnikov, H Qian, X Li, O Lishilin, D Melkumyan, A Oppelt, Y Renier, T Rublack, H Huck, Y Chen, F Stephan Deutsches Elektronen-Synchrotron, Platanenallee 6, Zeuthen, D-15738, Germany T Kozak, M Felber Deutsches Elektronen-Synchrotron, Notkestrasse 85, Hamburg, D-22603, Germany E-mail: Sergei.Mironov@mail.ru, alex.v.andrianov@gmail.com, gacheva@appl.sci-nnov.ru, vvmailv@mail.ru, ptmk@appl.sci-nnov.ru, khazanov@appl.sci-nnov.ru, mikhail.krasilnikov@desy.de, frank.stephan@desy.de Received 16 May 2017 Uspekhi Fizicheskikh Nauk 187 (10) 1121 ± 1133 (2017) DOI: https://doi.org/10.3367/UFNr.2017.03.038143 Translated by A L Chekhov; edited by A Radzig CONFERENCES AND SYMPOSIA PACS numbers: 29.20. ± c, 29.27.Ac, 42.60.By, 42.60. ± v Spatio-temporal shaping of photocathode laser pulses for linear electron accelerators S Yu Mironov, A V Andrianov, E I Gacheva, V V Zelenogorskii, A K Potemkin, E A Khazanov, P Boonpornprasert, M Gross, J Good, I Isaev, D Kalantaryan, T Kozak, M Krasilnikov, H Qian, X Li, O Lishilin, D Melkumyan, A Oppelt, Y Renier, T Rublack, M Felber, H Huck, Y Chen, F Stephan DOI: https://doi.org/10.3367/UFNe.2017.03.038143 Contents 1. Introduction 1039 2. Generation of high-brightness electron beams in modern photoinjectors 1041 2.1 PITZ linear accelerator; 2.2 Numerical optimization of PITZ photoinjector for various shapes of laser pulses 3. Three-dimensional shaping of laser pulses 1044 3.1 Photocathode laser at PITZ linear electron accelerator; 3.2 Controling the pulse shape using a profiled, chirped volume Bragg grating; 3.3 Experimental generation of quasitriangular pulses 4. Generation and characterization of electron beams at PITZ photoinjector 1046 5. Conclusion 1049 References 1050 Physics ± Uspekhi 60 (10) 1039 ± 1050 (2017) # 2017 Uspekhi Fizicheskikh Nauk, Russian Academy of Sciences