An apparatus for, and method of, single sign-on collaboration among a plurality of mobile devices, includes a server for issuing a first identity token to subsequently authenticate a user of a first of the mobile devices to a service provider, and for generating and sending a collaboration key to the first device based on the first identity token or user authentication. In the power-supply device, an output power signal is fed back to an error amplifier after having passed through a CR smoothing filter provided independently of a power LC smoothing filter. In one embodiment, a first beam of laser energy is directed through a scanning mechanism toward an eye to ablate the eye, and a second beam of laser energy is directed through the scanning mechanism toward a sensor.