Generation of a transient short pulse X-ray laser using a traveling-wave sub-ps pump pulse

This paper summarises die main results obtained during the two experimental campaigns on TCE X-ray lasers that we have carried out since the last Kyoto X-ray laser Conference in 1998. A two-color (2 omega /1 omega) pumping configuration was tested and led to the observation of a strong lasing line at 16 nm, identified to a 4f-4d transition in Ni-like Ag. A strong x 300-400 enhancement of the 13.9 nm Ni-like 4d-4p lasing emission was obtained when a traveling wave short pulse pumping was applied. Finally the temporal history of the 13.9 nm laser pulse was measured with a high-resolution Streak camera, A very short 2 ps X-ray laser pulse was directly demonstrated for the first time.

Developments in X-ray laser pumping with travelling wave at Vulcan

Saturated output has been observed for both Ne and Ni-like X-ray lasers when Pumped in the transient mode. As these 'normal' transitions display very high gain, attempts have been made to observe a 2p --> 2s inner shell transition in Ne-like ions, which scale well towards the water window. Modelling of the pump conditions for Ge lasing at 6.2 run is presented. As the predicted gain is low the experiment was set up for 18 mm targets. Shots were taken on Ti, Fe, Ni and Ge. A similar to1.5 ps travelling wave pulse is applied at various times after the peak of a long, preforming Pulse. Various pump conditions were attempted but no inner shell X-ray laser was detected.

Short pulse pumped X-ray lasers

Double laser pulses of duration similar to 75 ps and short laser pulses similar to 1 ps superimposed on longer duration background pulses have been shown to efficiently pump lasing in Ne-like and Ni-like ions. For the 75 ps pumping, X-ray laser output without travelling wave pumping is shown to be well-described by a model of ASE output. With I ps pumping, the X-ray laser output with different velocity travelling wave pumping is well-fitted with an extension to the ASE model allowing for travelling wave excitation of the gain along the plasma line. The model is used to investigate the production of short (<1 ps) x-ray laser pulses and the effects of non-ideal travelling wave velocities on the X-ray laser output. Resonance line spectra of emission perpendicular to the plasma line are measured and simulated. It is shown that an accurate opacity model for the more intense Ne-like ions is needed to correctly simulate the spectra.

Macroscopicity in an optomechanical matter-wave interferometer

We analyse a proposal that we have recently put forward for an interface between matter-wave and optomechanical technologies from the perspective of macroscopic quantumness. In particular, by making use of a measure of macroscopicity in quantum superpositions that is particularly well suited for continuous variables systems, we demonstrate the existence of working points for our interface at which a quantum mechanical superposition of genuinely mesoscopic states is achieved. Our proposal thus holds the potential to affirm itself as a viable atom-to-mechanics transducer of quantum coherences.