Fig. 1. Schematic diagram of GaAs p-i-n structure

Fig. 2. Transient photocurrent generated by GaAs p-i-n structure with thickness of i-layer of 4 μm and 0.4 μm with or without interference effect

Fig. 3. Waveforms of terahertz pulses generated by GaAs p-i-n structures with different thicknesses of i-layer and with or without considering interference effect. (a) Time-domain waveforms; (b) corresponding frequency spectra

Fig. 4. Trends of photocurrent peak amplitude and terahertz electric field intensity peak amplitude with thickness of i-layer from 0.4 to 4 μm with or without considering interference effect. (a) Trends of photocurrent peak amplitude; (b) trends of terahertz electric field intensity peak amplitude

Fig. 5. Influence of interference effect on terahertz wave generation under different thicknesses of i-layer. (a) Change of terahertz pulse energy with or without considering interference effect; (b) change of interference effect factor

Fig. 6. Trend of terahertz pulse full-width at half-maximum with thickness of i-layer from 0.4 to 4 μm with interference effect considered