An optically initiated device comprising a case comprising an energetic charge, a booster charge embedded in said energetic charge and a primer assembly to initiate said energetic charge, said primer assembly comprising an optical source wherein the booster charge comprises a flashtube embedded in said energetic charge and a primer container containing a sensitive energetic primer of variable density and wherein said optical source produces sufficient light fluence to ignite said sensitive energetic primer, which ignited primer in turn ignites into said flashtube, and which ignited flashtube in turn ignites said energetic charge.