X-ray contact microscopy using an excimer laser plasma source with different target materials and laser pulse durations

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-100 nm resolution, We have developed a table-top pulsed plasma S-ray source for this application, generated by a large-volume XeCl laser, achieving a good conversion efficiency to 'water-window' X-rays (hv approximate to 280-530 eV). Optimum plasma conditions for SXCM are discussed, including the effect of pulse duration, target material and resist development time on image resolution. Soft X-ray contact images of Chlamydomonas dysosmos (unicellular alga) and of the cyanobacterium Leptolyngbya are shown.