Fig. 1. Schematic diagram of tilted-pulse-front pulse^[28]

Fig. 2. Schematic diagram of four-wave mixing mechanism^[56]. (a) Four-wave mixing between fundamental frequency optical pulse and second harmonic optical pulse; (b) four-wave mixing in fundamental frequency spectral bandwidth

Fig. 3. Schematic diagram of terahertz generation by photocurrent^[57]

Fig. 4. Theoretical schematic and experimental setup of terahertz radiation generated from plasma^[63]. (a) Theoretical schematic; (b) experimental setup

Fig. 5. Schematic diagram of target back radiation^[78]. (a) Transition radiation; (b) sheath field radiation

Fig. 6. Schematic diagram of linear mode conversion to generate terahertz waves^[115]

Fig. 7. Tunable terahertz source generation from magnetized plasma^[120]

Fig. 8. Study of proportional share of target-back terahertz radiation in different mechanisms^[131]. (a) Schematic illustration of THz-generation scenarios at rear side of laser-irradiated foil; (b) spectral profiles for TR(red), BR(blue), and SR(green); (c) resultant radiation spectra from TR, BR, and SR; (d) three lineouts (at 100 fs, 1 ps, and 10 ps) taken from (c)

Fig. 9. Plasma channel generates tunable terahertz waves^[154]