The parameters of plasma, produced by a tightly focused, Q-switched ruby laser with energy 200mJ in $N_2$ gas, are experimentally estimated by the spectroscopic method, and their gas pressure dependence is studied. The gas pressures are varied between 1 and 4 atmospheric pressure. The Stark broadening of spectral lines emitted from plasma is used in the estimation of electron densities. The typical density is about order of $10^{19}[cm^{-3}]$. The electron density of plasma is increased as the gas pressure is increased. But the tempeature dependence was decreased as the gas pressure is increased.
Q-switching된 에너지 170mJ의 루비레이져에 의해 생성된 질소 가스플라즈마로부터 플라즈마 파라미터 즉 온도와 전자밀도가 압력 1기압, 2기압, 4기압에서분광학적 방법에 의해 측정되었다.
전자밀도는 약 $10^{19} (cm^{-3})$ 정도 였으며 압력에따라 약간 높아졌다. 그리고 온도는 1기압에서 약 1.eV 정도로 추정되었다.
