On January 30, 2011, Omid Kokabee, 28, was about to board a flight to the United States at Tehran airport. He was returning to his doctoral studies at the University of Texas at Austin after spending a winter break with his family. Halfway through the gate he was stopped by Iranian intelligence officers, taken to Tehran's Evin prison and placed in a solitary confinement.

During the 15-month pre-trial period Kokabee was not allowed any contact with the outside world. He was sentenced to 10 years in prison "for communicating with hostile government (meaning the United States) and illegal earnings (meaning his doctoral student stipend at UT-Austin)".

Last year, thirty-three physics Nobel laureates appealed to the Iran's Supreme Leader on his behalf. In December 2014 the Supreme Court of Iran ruled that the case documents contained no evidence of any crime committed by Kokabee but his release from prison has been blocked by another government agency.

To understand why Iran is keeping in prison a scientist who has not committed any crime and who stayed away from politics prior to his arrest, one should look at the events preceding his arrest. Just one day before, he was invited to the office of a high-ranking official of the Atomic Energy Organization of Iran (AEOI) and offered a job in the AEOI division working on high-intensity carbon dioxide lasers.

Although this was Kokabee's area of expertise (he studied high-intensity lasers at Tehran's Sharif University and then at the Institute of Photonics in Barcelona before transferring to UT-Austin), he politely declined. This might have sealed his fate.

One of the uses of high-intensity carbon dioxide lasers is uranium enrichment through separation of isotopes by laser excitation (SILEX). The method was developed in 1990s by an Australia-based company and licensed to the United States Enrichment Corporation.

Former Iranian President Mahmoud Ahmadinejad, speaking on the 31st anniversary of the Iranian Revolution in February 2010, admitted the existence of the SILEX program in Iran when he declared that "thanks to relentless efforts by Iranian scientists", the country now possessed laser enrichment technology that allowed uranium production "with a higher quality, accuracy, and speed" than with centrifuges.

Nuclear negotiations with Iran are focused on the number of centrifuges that Iran will be allowed to operate. It would be interesting to know whether any limits on laser enrichment technology have been discussed as well.

Eugene M. Chudnovsky is a Distinguished Professor of Physics at the City University of New York and Co-chair of the Committee of Concerned Scientists. Thinking of submitting an op-ed to the Washington Examiner? Be sure to read our guidelines on submissions for editorials, available at this link.