08 Aug 2003
US fiber laser specialist IPG Photonics develops a source that emits at the very far edge of human vision.
IPG Photonics, the US-based fiber laser manufacturer that has stirred up the industrial laser market with its high-power sources, has developed a laser that operates in the red.
The ELP-775 is a frequency-doubled erbium fiber laser with a central wavelength of 775 nm. IPG says that the diffraction-limited, singlemode output is tunable between 770 and 780 nm, at a power level of 5-30 W. Pulse frequency can be adjusted between 10 and 20 MHz, while the pulse duration is 2-3 ns.
The operating wavelength is right at the edge of human visual perception, but according to IPG’s Bill Shiner, it can be seen: “It is bright and dark red in color,” he told Optics.org.
According to color experts Alison Gilchrist and Jim Nobbs at the University of Leeds Department of Colour Chemistry, UK, light at 780 nm appears seven orders of magnitude less bright than it does at 510 nm (the wavelength of maximum sensitivity for rod cells, which we use for seeing in the dark).
“In other words, it’s pretty dim,” said Gilchrist.
IPG claims that the source will make a significant impact in micromachining, scientific, medical, marking and visual arts applications.
IPG chief executive Valentin Gapontsev says that the red laser is just the first of a variety of sources emitting in the visible region that the company has planned. “According to our roadmap, the next step would be a 5 W near-UV laser at 385-390 nm, as well as precise and powerful pulsed and continuous-wave fiber lasers for the green and blue spectral bands.”
• Optics.org would like to make it clear that although a beam at 780 nm may appear very dim, it is hazardous to the eye and appropriate eyewear should be worn.
• 780 nm is right at the edge of human visual perception. Can you see light at this wavelength? Comment on this story here.
Michael Hatcher is technology editor of Opto & Laser Europe magazine.