Direct ninth harmonic conversion of picosecond laser pulses

Higher-Order Processes

“…13, show an increase in total fifth harmonic and movement of the peak of the curve toward smaller values of bAk 15 as the indirect process becomes important. Analytic expressions for the imaginary part of They have also given calculations for the net fifth harmonic generated from focused beams when both the direct and indirect processes are important.…”

“…Radiation at several wavelengths ranging from 38 to 118.2 n m has been generated through higher-order processes involving harmonics of N d : Y A G , 5 -1 3 ' 3 2 N d : g l a s s , 15 and XeCl lasers. 14 The wavelengths of the generated radiation along with the pumping wavelengths, the pumping lasers, and the nonlinear processes are listed in Table 3.…”

“…The phase optimization integrals F 3 and F 5 for a semi-infinite medium are given by F 3 (bAk 13 , oo,0) = -n(bAk l3 /2)e bàk " /2 + i[l + (bAk 13 /2)e hàk " 12 χ Ei(bAk 15 /2y], Ak 15 >0, (81b) where Ei(x) and E t (x) are exponential integrals.…”

“…These are listed in Table 4. The experiments reported in Grozeva et al 15 were done in focused beams for which the phase-matching ratio for the direct process 16.7 and that for the first indirect process was 4.73. Level diagrams for these two interactions in N a and Ar are shown in Fig.…”

“…General properties of the higher-order interactions have been treated by Akhmanov. Ninth-harmonic conversion of Nd:glass radiation has been observed by Grozeva et al 15 Puell et al 16 have discussed the role of fifth-order processes in limiting third-harmonic conversion. H a r r i s 3 has suggested the use of the higher-order interactions for the generation of radiation in the extreme ultraviolet and soft x-ray special ranges.…”