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Princeton University researchers have reexamined longstanding beliefs about the physics of lasers and have shown that by restricting power to certain areas could boost its output.

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Turning loss to gain
By reexamining longstanding beliefs about the physics of lasers, Princeton University engineers have shown that by carefully restricting the delivery of power to certain areas within a laser could boost its output by many orders of magnitude.

The team believes this finding could enable more sensitive and energy-efficient lasers, as well as potentially more control over the frequencies and spatial pattern of light emission.

The team said it is as though loss is being used for an advantage.

The researchers explained that restricting the delivery of power causes much of the physical space within a laser to absorb rather than produce light, but in exchange, the optimally efficient portion of the laser is freed from competition with less efficient portions and shines forth far more brightly than previous estimates had suggested.

While based on mathematical calculations and computer simulations, the results still need to be verified in experiments with actual lasers, and the researchers stressed that this represents a new understanding of the fundamental processes that govern how lasers produce light.

If borne out in actual lasers, the results could lead to laser devices becoming more portable, the team said. For example, a gas sensor for environmental field research or a medical diagnostic device that would have required a wall outlet, might be able to function with just batteries.

Engineers at Princeton found that carefully shaping the area to which energy is delivered within a laser could dramatically improve the laser's performance. In the case illustrated, pumping energy into a diamond shape produces a powerful directional emission of light from the laser. (Source: Princeton University, Department of Electrical Engineering)

Engineers at Princeton found that carefully shaping the area to which energy is delivered within a laser could dramatically improve the laser’s performance. In the case illustrated, pumping energy into a diamond shape produces a powerful directional emission of light from the laser. (Source: Princeton University, Department of Electrical Engineering)