The laser system L3-HAPLS represents a new generation of diode-pumped, high-energy and high-peak-power laser systems. Once completed it will set a world record for most intense diode-pumped petawatt lasers. The laser system will serve in many areas of basic and applied research. Its most significant applications include compact laser particle accelerator for new medical methods and short-wave X-ray generation for high resolution spatial and temporal resolution microscopy for material and medical research. The initial experiments will be capable of taking images with resolution orders of magnitude better from what is seen in today’s hospitals.