X-ray contact microscopy using a plasma source generated by long and short (120-ns and 10-ns) excimer laser pulses

Soft x-ray contact microscopy (SXCM), using a pulsed x-ray source, offers the possibility of imaging the ultrastructure of living biological systems at sub-50nm resolution. We have developed a pulsed plasma x-ray source for this application, generated by the large volume XeCl laser 'Hercules'. Various unstable optical resonator configurations were employed to achieve a high laser intensity to increase the conversion efficiency to 'water window' x-rays (280-530eV). Optimum plasma conditions for SXCM are discussed, including the effect of pulse duration on image resolution. Soft x-ray contact images of Chlamydomonas dysosmos (unicellular alga) and the cyanobacteria Leptolyngbya are shown. In addition, the potential of producing a 'movie film' of the development of x-ray images within the photoresist (acting as the recording medium) is discussed, following the resist development while viewing by atomic force microscopy.