A rare type of ROM. Voltage levels are set by firing a laser at traces to set/clear bits.

|{{gallery>:image:sergei_p_skorobogatov_016_laser_rom.jpg}}|
|Original caption: "Laser ROM in Dallas DS1961S iButton chip. Information can be read optically and altered with a laser cutter."  Copyright 2005 Sergei P. Skorobogatov, used with permission|

====== References ====== 
  - "Semi-invasive attacks - A new approach to hardware security analysis." Sergei P. Skorobogatov.
  - http://www.maxim-ic.com/datasheet/index.mvp/id/3557