Fig. 1. Experimental setup of two-stage optical parametric amplifier

Fig. 2. White light supercontinuum spectra measured at the front surface of lens L2 under different coordinates. (a) Linear coordinate；(b) logarithmic coordinate

Fig. 3. Pulsed spectra before and after preamplification. (a) White light supercontinuum spectrum before preamplification (measured at the front surface of BBO crystal C2) after filter; (b) white light supercontinuum spectra after preamplification (from left to right: 520, 530, 550, 570, 590 nm); (c) spectra of idler light after preamplification (from left to right: 1240,1340,1467,1630,1745 nm)

Fig. 4. Output pulse spatial characteristics after preamplification. (a) Signal light (550 nm)；(b) idler light (1467 nm)

Fig. 5. Output characteristics of different wavelength pulses of power amplification. (a) Output spectra of signal pulse (1350 nm) and idler pulse (1963 nm); (b) output spectra of signal pulse (1450 nm) and idler pulse (1785 nm); (c) output spectra of signal pulse (1540 nm) and idler pulse (1665 nm) ; (d) output spectra of signal pulse (1733 nm) and idler pulse (1485 nm); (e) output spatial characteristics of signal pulse(1450 nm); (f) output spatial characteristics of idler pulse (1785 nm)

Fig. 6. Output characterization after two-stage amplification. (a) Output energy under different signal wavelengths; (b) quantum conversion efficiency under different signal wavelengths

Fig. 7. Pulsed time-domain curves fitted by autocorrelator after two-stage amplification. (a) Signal pulse (1467 nm)；(b) idler pulse (1800 nm)