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At the beginning of the year, Hong Tang, Professor of Electrical Engineering at Yale University, and his team developed the world’s first chip-sized titanium:sapphire laser, shrinking a laser that would conventionally take up an entire table length to just a few centimeters. Titanium:sapphire lasers have been one of the most important advancements in laser development. The coupling between the sapphire crystals and active titanium ions results in the largest emission spectrum of any solid-state material, allowing researchers to exploit this powerful property to amplify and direct energy. However, the bulky commercial titanium:sapphire lasers require an immense amount of power, so they are often costly and limited to industrial lab environments.
“A few years ago we were thinking, why don’t we miniaturize this titanium:sapphire laser and put it on an integrated photonic chip platform,” said Yubo Wang, lead author and graduate student in the Tang lab. This new model minimizes the area to a chip while still preserving the performance of the full-sized titanium:sapphire laser, allowing for portability and minimal power consumption. They were able to accomplish this feat by bringing down the energy threshold from more than one hundred milliwatts to less than seven milliwatts.
The Tang lab continues to work on iterations of the chip-sized laser and aims to achieve an even lower threshold (around one milliwatt) and higher output power. Not only is this new model a reduction in size, but also a steep reduction in price. Wang expects that at large-scale manufacturing, the laser could cost less than a thousand dollars, more than a three-fold decrease in price. “Miniaturization of the titanium:sapphire laser will bring about many applications, especially those sensitive to power consumption and size, such as integrated atomic clocks, portable sensors, visible light communication devices, and quantum computation chips,” Wang said.