Compact disc and DVD players use lasers, which Einstein first theorized in 1917 in advancing his work on the photoelectric and photovoltaic effects.

• 光盘和DVD播放机利用了激光，而爱因斯坦1917年在推出其有关光电效应和光生伏打效应的研究成果时，最先提出了这方面的理论。