Production of picosecond square-shaped ultraviolet pulses for low-emittance electron bunch generation from an RF photocathode

Akira Yada, Kazuya Takasago, Shinji Ito, Tatsuya Yanagida, Jinfeng Yang, Masakazu Washio, Kenji Torizuka, Akira Endo

Research output: Contribution to journalArticle


We demonstrated generation of square-shaped ultraviolet pulses and that they reduces the emittance of electron beams from laser-photocathode RF-gun. Some frequency components of femtosecond pulses from a Ti:sapphire oscillator are modulated with a pulse shaper that consists of a lens pair, gratings, and a liquid crystal spatial light modulator (LC-SLM) to generate square-shaped pulses. The shaped pulses were amplified up to 3 mJ through a regenerative amplifier, and were converted to ultraviolet region with two different nonlinear crystals. Energy of the shaped pulses was about 100 μJ which is sufficient to generate electron charge of 1 nC. In our experiment, emittance of electron beam was reduced to as low as almost the half of that with non-shaped pulses.

Original languageEnglish
Pages (from-to)213-221
Number of pages9
JournalProceedings of SPIE-The International Society for Optical Engineering
Publication statusPublished - 2002 Jan 1



  • Emittance
  • Flat top
  • Pulse shaping
  • RF-gun
  • Square pulse
  • Ultraviolet

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering

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