Fig. 1. Three different excitation source experimental devices
(a): Nanosecond pulse; (b): DC self-pulse; (c): Microwave

Fig. 2. P atom line and PO molecule band in MW plasma with argon carrier gas

Fig. 3. OES from Microwave plasma before and after DMMP is introduced
(a): Before the introduction of the DMMP;(b): After the introduction of the DMMP

Fig. 4. OES of DMMP from nanosecond pulse discharge (a) and DC self-pulse discharge (b)

Fig. 5. Spectra fitting of different excitation sources
(a): Microwave; (b): Nanosecond pulse; (c): DC self-pulse

Fig. 6. Principal component analysis diagram

Fig. 7. Linear fitting of frequency and spectral intensity