Exalos is a developer of superluminescent LEDs. These are LEDs that have a spectral width that is similar to conventional LEDs but with the output beam characteristics of a laser. Lasers also use an optical cavity to increase the power output so they are very efficient, but with narrow spectral output and speckle. SLEDs use a single pass through a waveguide to increase power over an LED, but not to the level of a laser. However, there is now no speckle. The table below summarizes the main differences between lasers, LEDs and SLEDs.
Exalos was in the i-Zone at SID where they were showing their blue and red SLEDs. The photo below shows a comparison between RGB laser diode (top) and the RB SLEDs below. Note the similar beam profile but lack of speckle.
Obviously, Exalos needs to develop a green SLED for any full color display application. And, in fact, they are actively working on this now and expect to offer a 515nm model soon. The blue SLED is currently at 440nm (100mW, 6nm FWHM and >5% WPE), but a 450nm version is coming by year end. The red is now at 650nm (50 mW and 6nm FWHM) with a 638nm version coming by the end of August. These newer wavelengths are better suited for the BT.2020 color gamut. The green at 515nm is not the best choice, but it may be the only one the company is able to achieve at this time. – CC
