Chimera was the special code name given to a project developed by the Tau'ri.
The Chimera Optics Projection System (Chimera for short) is Earth's attempt at replicating the holographic technology of the Asgard race. It is an advanced method of creating realistic 3D images that are created virtually. Projections appear real, but are actually created through the use of advanced holographic technology. (SG1: "Covenant", "Bounty")
The first "mock" display of this system was in direct response to Alec Colson's attempt to show the world that aliens existed. Lt. Colonel Samantha Carter was then ordered to publicly discredit Alec Colson with help from Thor by using the holographic technology of the Asgard. Carter went on !nside Access to convince the public that it was simply a hologram that they saw during Alec Colson's press conference. This allowed the government to maintain the secrecy of alien contact and subsequently the Stargate Program. She claimed that the United States Air Force was developing the technology and that it might eventually make it to the civilian field for amusement parks as well as other such attractions. (SG1: "Covenant")
The actual first display Chimera was by Lt. Colonel Samantha Carter and Dr. Bill Lee at a scientific conference. Chimera saved her life as an assassin shot at her hologram on stage, thus, exposing his position. She then shot him with the X-699. She officially gave the name Chimera Optics Projection System for the technology and highlighted it as a development to the science community. SG-1 then used Chimera to trick and capture Odai Ventrell. (SG1: "Bounty")