Page 10 - Demo

into a 3 micron beam footprint, this corresponds to a0 = 0.79 where a0 = eE/(mec0) = 0.85L(I/1018)1/2 where L is the laser wavelength in micro-meter and I is the laser intensity in W/cm2. Foil composed of deuterium is used for the target with density of 1.0x1023 cm-3. Table 1 shows the efficiency of the energy conversion from laser to ions sensitively depends on the pulse length. It has been shown previously [12] that a0= results in the highest efficiency where = ne/ncr*d/L with ne is electron density, ncr critical density (=meL2/4e2 =1.1x1021/m where L is the laser frequency and m is the laser wavelength in m), d is foil thickness and L is laser wavelength. The theoretically maximum energy is given under the optimal condition of a0 [12] as
. (1)
Pulse [fs]
Efficiency [%]
13.8
2.3
27.7
7.0
34.7
9.2
41.9
8.9
50.1
8.1
70.2
6.2
100.5
5.5
Table 1: Laser to deuteron conversion efficiency for various pulse lengths under the condition of  = a0.
Figure 4 shows the details of the laser system. The typical laser energy required for the regime amounts to only a few mJ per pulse. This opens up a window to introduce a new class of intense and ultrashort laser via fiber. The laser driven neutron source relies on the CPA [42] - Based XCAN [35] provides a high-energy high-pump pulse for the OPCPA [43] and [44]. The