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

Abstract

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 X‐ray source for this application, generated by a large‐volume XeCl laser, achieving a good conversion efficiency to ‘water‐window’ X‐rays (hν≈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.