Efficient Generation of Coherent Soft X-Ray Radiation

WPCD 2 B V P Z 10cpi ? x x x， K x 6 X @ 8 ; X @ HP LaserJet Series II HPLASEII.PRS X @ , t 0 OpX @ #|X 2 B 9224520 Milchberg通过强皮秒和亚皮秒脉冲与中等密度稀有气体的非线性相互作用产生相干真空紫外和软X射线辐射是一个非常实用和基本感兴趣的领域。 我们提出的实验，以解决一些问题，已经出现在该领域，并从答案的发展更有效的源的相干，软X射线辐射。 (i)将使用双色实验研究由强激光场引起的原子共振的偏移对高谐波产生效率的影响：较长（100 ps）的红外脉冲来偏移能级，以及延迟的亚皮秒可见脉冲来产生谐波。(ii)离子在产生谐波中所起的作用将使用单色和双色泵浦探测技术来确定。 (iii)高次谐波（长脉冲和短脉冲产生）的高精度光谱将用6.7 m真空紫外光谱仪进行。 (iv)将研究涉及两个驱动波长的多波混频，以实现有效的相位匹配和近共振条件。 预计这将显著提高短波长产生的效率。 (v)我们最近在强短激光脉冲的光学引导方面取得的成功也将被用来确定引导结构对谐波产生效率的影响。***

WPCD 2 B V P Z Courier 10cpi ? x x x , k x 6 X @ 8 ; X @ HP LaserJet Series II HPLASEII.PRS x @ , t 0 OpX @ #| x 2 B 9224520 Milchberg The generation of coherent vacuum ultraviolet and soft X ray radiation by the nonlinear interaction of intense picosecond and subpicosecond pulses with moderate density rare gases is an area of great practical and fundamental interest. We propose experiments to address a number of questions that have arisen in the field and to proceed from the answers to the development of more efficient sources of coherent, soft X ray radiation. (i) The effect of shifting of atomic resonances by an intense laser field on the high harmonic generation efficiency will be investigated using a two color experiment: a longer (100 ps), infrared pulse to shift the levels, and a variably delayed subpicosecond visible pulse to generate harmonics. (ii) The role played by ions in generating harmonics will be determined using both one and two color pump probe techniques. (iii) High precision spectroscopy of the high harmonics (generated with both long and short pulses) will be performed with a 6.7 m VUV spectrometer. (iv) Multiwave mixing involving two driving wavelengths will be studied to achieve efficient phase matching and near resonant conditions. This is expected to dramatically increase the efficiency of short wavelength generation. (v) Our recently achieved success in optical guiding of intense short laser pulses will also be exploited to determine the effect of guiding structures on harmonic generation efficiency. ***