In view of the issue of insufficient sensitivity in laser-induced plasma (LIP) technology for live detection of vacuum circuti breaker

in this paper a surface nanocrystallization technique based on gold nanoparticle (Au NP) enhanced laser-induced plasma is propsoed. The enhancement of Au NPs with varying particle sizes under different delay times on the spectral signals of copper targets at low pressure are systematically investigated. The results show that Au NPs can significantly enhance spectral signals under low-pressure conditions

reducing the detection limit down to 10

-4

Pa. The enhancement effect of 5 nm particles at a 100 ns delay time is the most optimal

yielding a maximum enhancement factor of 13.55 and an average enhancement factor of 6.7

7. With the increase of the pressure

the enhancement effect exhibits a linear decline. However

Au NPs can still effectively mitigate the negative impact of pressure on plasma radiation. Furthermore

Au NPs prolongs the plasma signal duration through localized surface plasmon resonance (LSPR)

confining the plasma to the initial expansion stage and improving the fitting accuracy (

R

2

= 0.999 8) of the radiation integral intensity. This study has revealed the enhancement mechanisms of Au NPs under low-pressure conditions and provided higher precision for online vacuum detection of vacuum circuti breaker.