| CPC G01N 21/718 (2013.01) [G01J 3/1809 (2013.01); G02B 27/1006 (2013.01)] | 14 Claims |

|
1. A multipulse-induced spectroscopy method based on a femtosecond plasma grating, comprising:
pre-exciting a sample on a stage by providing a femtosecond pulse to form the femtosecond plasma grating;
providing a post-pulse on the sample at an angle to excite the sample to generate a plasma, wherein the post-pulse comprises one or more femtosecond pulses, there is a time interval between the femtosecond pulse and the post-pulse, and the time interval is less than a lifetime of the femtosecond plasma grating; and
receiving and analyzing a fluorescence emitted from the plasma to determine element information of the sample;
wherein the method further comprises:
splitting the femtosecond pulse into three sub-pulses; and
adjusting an optical path of each of the three sub-pulses in such a way that a first pulse and a third pulse of the three sub-pulses have an optical path with a first length and arrive at the intersection in space simultaneously to form the femtosecond plasma grating, and a second pulse of the three sub-pulses has an optical path with a second length being different from the first length and arrives at the intersection in space after a preset time interval;
wherein splitting the femtosecond pulse into three sub-pulses comprises:
splitting the femtosecond pulse into the first pulse and a primary reflection light; and
splitting the primary reflection light into the second pulse and the third pulse.
|