1 Table of Contents: “... quantum well blue-green lasers -- Low threshold current density wavelength shifting between N=1 and N=2...”

2 “... understand these exciting new developments. It also discusses recently established applications, such as blue...”

3 “... reviewing the research field and the laser fundamentals, there are comprehensive updates on red and blue...”

4 “...Why is the sky blue? What is the nature of light? What can visual illusions tell us about...”