A shock wave reflector includes a number of reflective units positioned along a longitudinal direction and separated by a gap G. Each reflective unit has a length L. The length L and the gap G are governed by a relationship L+G≧λ. The variable λ characterizes a cell size for a detonation mixture. A detonation chamber includes a receiving end, a discharge end, and a wall extending along a longitudinal direction between the receiving and discharge ends. The detonation chamber further includes a number of reflective units formed in the wall and positioned along the longitudinal direction. The reflective units are separated by a gap G, and each reflective unit has a length L.