Date: Wed, 21 Dec 2011 09:47:06 +0900
From: Norihiro Sei 

Dear FEL Community,

   I am glad that I inform you an experimental achievement of a
seventh-harmonic FEL oscillation at the National Institute of Advanced
Industrial Science and Technology (AIST) in Japan. 

   An FEL team at the AIST has developed higher-harmonic FEL
oscillations using the storage ring NIJI-IV and its infrared FEL
beamline. We have already achieved the third-harmonic FEL oscillations
in a wavelength region of 852-1551nm. Using high-reflectivity dielectric
mirrors, the fifth- and seventh-harmonic FEL oscillations were achieved
at wavelengths of approximately 890 nm. The characteristics of the
higher-harmonic FELs were described in the following article:  

   N. Sei, H. Ogawa, and K. Yamada, "Operation of higher harmonic
oscillations in free-electron lasers," Opt. Express 20, 308-316 (2012).  

   Our results would be helpful to recognize again the usefulness of the
higher-harmonic FEL oscillation. The higher-harmonic FEL oscillation
technique is useful for realizing a resonator-type FEL with lower
electron-beam energy in the EUV and x-ray regions. I expect that a
high-power resonator-type FEL with the higher harmonics will be applied
to the photolithography at a wavelength of 13 nm or less.

   Although a press release from the AIST cannot be carried out, I thank
for what I can inform you our results at this place. 

   I hope that your research is going well. 

Yours sincerely,

 Norihiro Sei 
 Research Institute of Instrumentation Frontier 
 National Institute of Advanced Industrial Science and Technology 
 1-1-1 Umezono, Tsukuba, Ibaraki Japan  305-8568                             
 (TEL) +81-29-861-5680   
 (FAX) +81-29-861-5683