A single multiwalled carbon nanotube (MWNT)‐glass fiber is used to monitor the initiation and growth of microcracks in composites, which provides an early warning system to detect fracture in materials. An electromechanical microswitch is further constructed based on the connecting/breaking of the nanotube bridges across microcracks under external strain or thermal expansion.

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Amplification of spontaneous emission (ASE) at 23.6 nm has been studied in a Ge plasma heated by a 1 TW infrared laser pulse. The exponent of the axial gain reached 21 in a geometry with Fresnel number < 1. Two plasma columns of combined length up to 36 mm were used with an extreme ultraviolet mirror giving double-pass amplification. Saturation of the ASE output was observed. The beam divergence was about 8x diffraction limited with a brightness estimated at 10 14 Wcm~2sr _1 . The feedback from the mirror was significantly reduced probably by radiation damage from the plasma.