[3] Following a period of private ownership by the Japanese firm Sumitomo Heavy Industries Ltd. starting in 1989,[4] it once again went public in 1995 and went on to merge with Massachusetts-based General Scanning Inc. in 1998/99, to become GSI Lumonics, “the largest producer of laser-based manufacturing equipment in the world".

[13] As paraphrased by The Globe and Mail, one day “over cocktails”, the wives of “fellow neighbors and weekend pilots”, Al Buchanan and Gord Mauchel, “wondered aloud why the two did not quit their jobs and start their own business.

That summer the tentative company submitted, and successfully won, an application for the right to manufacture and sell Transversely Excited Atmospheric (TEA) gas lasers invented at the Government's Defence Research Establishment in Val-Cartier, Quebec.

[23][3] After another $10 million share issue to institutional investors in January 1983, a subsequent 2 for 1 stock split, and a 250% increase in orders at the JK subsidiary, construction was begun on a new 50,000 square foot plant there.

[24] In March of the following year, Laser Identification Systems, which had just commenced operations in a new 23,000 square foot facility in Camarillo California, was officially adopted into the Lumonics Group of companies[25] to handle the expanding market for marking and engraving.

“Since commencing operations in 1979, [it had] established world dominance in computer-controlled laser systems used for marking silicon wafers produced by the rapidly expanding semiconductor industry".

[28] Following an $8.4 million acquisition of Photon Sources Inc. of Livonia, Michigan by the company in December of that year (as the subsidiary, Lumonics Material Processing Corp. or LMPC), in a surprise move the following March, Mauchel announced that he too would retire in September 1986, in turn handing over the reins to Atkinson, who added the third role of chairman to his existing ones as president and CEO,[29] until a new president, Hugh MacDiarmid, could be found and finally was appointed in March 1987.

In 1986, due to "the very disappointing financial results of [the] most recently acquired Photon Sources Inc", together with the overall effects of "a slow U.S. economy and depressed conditions in the semiconductor/electronics industry", Lumonics reported its first loss since 1971.

[36] Scott Nix, formerly VP of the US subsidiary, was promoted to the newly created position of president and COO at the end of the year[37] and eventually Sumitomo gave up its majority stake in another offering in 1997[38] (though continued to remain a significant shareholder until its bankruptcy in 2010).

[39] The money raised from the resulting share issue, combined with the company's cash reserves, gave it what many analysts considered "a formidable takeover kitty", with much speculation following as to who the target might be.

[40] In 1998, the company announced it would merge with Watertown Massachusetts based General Scanning Inc., to become GSI Lumonics, “the largest producer of laser-based manufacturing equipment in the world".

With the recession that followed in 2001, the local workforce was gradually reduced back down to only 200 again and early in 2002, after almost 30 years as head office, the Kanata facilities were finally "boarded up",[7][8] and “the real power shifted to the U.S. operations, where Chuck Winston, the chief executive at General Scanning and at GSI Lumonics, works".

[11] After the Lumonics name disappeared, only weeks before his death in 2005, original co-founder Alan Buchanan told the Ottawa Citizen: “I am deeply disappointed that technology invented in Canada and the traditions of a company that developed it could be abused in this way".

[50][51] On a technologically related front to Lumonics' primary business, Interoptics, which was acquired by them and renamed Lumonics Optics Group[52] (and later WavePrecision[53]) pioneered advanced optical manufacturing techniques and supplied many components to the telecom industry as well as constructing instruments for several space missions, in particular the MDI (or Michelson Doppler Imager)[54] which was then replaced with the HMI (or Helioseismic and Magnetic Imager), with LightMachinery building the Michelson interferometer.