Theoretical prediction of electromagnetically induced transparency for X-rays

Electromagnetically induced transparency (EIT) is a coherent optical nonlinearity, and brings dramatic changes in optical properties such as absorption, emission, refraction etc. The phenomena relate to the quantum mechanical overlapping state created by two different wavelengths of coherent light. Recently, EIT for X-rays has been theoretically predicted. According to the theory, it is possible to make Ne gas, which is normally opaque, transparent by exposing it to laser light of 800 nm with extremely high flux of 10¹² W/cm². The scheme could be used for producing ultra-short X-ray pulses. For more information, see the paper, "Electromagnetically Induced Transparency for X Rays ", C. Buth et al., Phys. Rev. Lett., 98, 253001 (2007). For more about general EIT, see, for example, "Electromagnetically Induced Transparency.", S. Harris, Physics Today, 50, 36-42 (1997).