Semiconductor lasers are small, reliable, low cost, high-performance and user-friendly optical devices which make them highly suitable for a variety of biomedical applications. This edited book gathers experts in the field to cover the fundamentals and technology advances of semiconductor lasers and diode-based lasers with a focus on their applications in medical optics and biophotonics including edge-emitting semiconductor lasers and light emitting diodes, Q-switched and mode-locked lasers, quantum cascade lasers, semiconductor disk lasers, near-infrared spectroscopy systems for biomedical applications, bio-medical Raman spectroscopy, nonlinear imaging and optical coherence tomography.