SHORT-WAVELENGTH LASING ON COLLISIONALLY PUMPED, HIGHLY EXCITED 2S HOLE STATES OF NEON-LIKE IONS IN PREFORMED PLASMAS, IRRADIATED WITH INTENSE PICOSECOND PULSES
Sb. Healy et al., SHORT-WAVELENGTH LASING ON COLLISIONALLY PUMPED, HIGHLY EXCITED 2S HOLE STATES OF NEON-LIKE IONS IN PREFORMED PLASMAS, IRRADIATED WITH INTENSE PICOSECOND PULSES, Optics communications, 144(1-3), 1997, pp. 24-30
Simulations of preformed germanium and yttrium plasmas irradiated with
intense greater than or equal to 10(15) W cm(-2) picosecond pulses ar
e presented. The results indicate that the combination of high electro
n temperature (similar to 2 keV) at electron densities of greater than
or equal to 10(21) cm(-3) can lead to lasing on 2s hole transitions a
t wavelengths of 62 Angstrom and 42 Angstrom for the germanium and ytt
rium respectively. In both cases, the small signal gain is considerabl
y smaller than that predicted for the mon usual 2p hole transitions be
cause it is limited by the large Doppler linewidths associated with th
e shorter wavelengths, However, the wavelength also leads to improved
sampling of the gain regions as refraction effects are reduced. The fa
r field patterns are characterised by deflected angles of similar to 5
mrad with narrow horizontal and vertical divergence. In addition, it
is shown that the output intensity can be enhanced by using curved tar
gets for lengths of similar to 2 cm. (C) 1997 Elsevier Science B.V.