Micro Laser, Just hard to see with naked eye.

Almost invisible Microlaser

Schematic of the electrically injected free-standing rolled-up tube laser, showing light emission from the center of the laser. Credit: M. H. T. Dastjerdi, et al. ©2015 AIP Publishing

How many times in your life do you see splendid presentations by pointed by a handheld laser pointer, I bet you can not count them at all. But now you can not even see it, yes  this new laser fabricated a team of engineers, lead by M. H. T. Dastjerdi, et al., at McGill University in Montreal a This laser is so tiny that you can fit 10 of these along length in 1 mm. Its diameter is only 5 micrometers—almost invisible to unaided human eye, unless you have a superhuman eye. 

Nanophotonics, which takes advantage of the much faster speed of light compared with electrons, could potentially lead to future optical computers that transmit large amounts of data at very high speeds. This is the first rolled-up semiconductor tube laser that is electrically powered. The good news for gadget lover is that it can fit on an optical chip and serve as the light source for future optical communications technology. Which means all-optical computing is now one step closer to us.

The article was published in a recent issue of Applied Physics Letters. M. H. T. Dastjerdi, et al. "An electrically injected rolled-up semiconductor tube laser." Applied Physics Letters. DOI: 10.1063/1.4906238  

The electrically injected rolled-up semiconductor tube lasers was fabricated by selective release of coherently strained InGaAs/InGaAsP quantum well heterostructure from the underlying InP substrate.This laser emits in IR at ∼1.5 μm, ideal for telecom wavelength range, at a lasing threshold of ∼1.05 mA. The measure of a The results were compiled at cryogenic condition at 80 K. Although this laser worked at subzero ultra low temperatures, however it holds promise for improved better lasers capable of lasing at room temperature.

Read more at: http://phys.org/news/2015-01-first-of-its-kind-tube-laser-on-chip-optical.html
  For the rolled-up quantum well tube laser, the maximum Purcell factor is estimated by

Fp = (3/4π ²)(λ c/neff)³ (Q/Veff),  

where λ c is the resonance wavelength, neff is the effective refractive index, and Veff is the effective mode volume. For the lasing mode, Quality factor Q is derived to be ∼800, and Veff and neff are estimated to be ∼4  μm³ and ∼2.26, respectively. The Purcell factor is then calculated to be ∼4.3.
Applied Physics Letters. DOI: 10.1063/1.4906238