Abstract: Micro-active medium ) MSI ( “Metal thin Silver film / p-Si<100>/ Glass” cavity was designed for micro and nano laser systems, based on ~120 nm metal thin Ag film in thickness, p-Si<100>and Glass 0.5 mm in thickness making cavity of material matrix ” MSI”. We have shown for the first time strong lasing in visible region “~625nm” from simple material cavity “MSI” after interaction with ”Ar+ ion laser, 514.5 nm: 0.7-0.8 watt” at room temperature. Si type was selected after PL study using He-Ne laser”543.5nm” and Ar+ ion laser”514.5” nm .We have obtained excellent results from PL study after thermal treated p-Si<100>. In this work, we discuss the origin of this lasing and explain the relationship between the surface texture of Si and output intensity of lasing action at red emission. We have found there is strong relationship between excitation power and ΔνFWHM of “MSI” matrix emission at room temperature.