Abstract: A light source, particularly suited for surgical and other medical illumination applications, includes an electrodeless lamp assembly, a reflector having the electrodeless lamp assembly mounted therein and high frequency power source for supplying high frequency power to the electrodeless lamp assembly. The electrodeless lamp assembly includes an electrodeless high intensity discharge lamp capsule including a light transmissive discharge envelope enclosing a discharge volume containing a mixture of starting gas and chemical dopant material excitable by high frequency power to a state of luminous emission. The luminous emission has a color rendering index greater than 85 and preferably has a color rendering index greater than 90. The luminous emission preferably has low energy in the spectral range of 800 to 1000 nanometers relative to energy in the visible spectral range.

Abstract: The present invention provides a method for using electrodeless high-intensity discharge (HID) lamps for automotive headlamp and similar applications requiring high/low beam operation (first and second beam orientation) of signaling. The HID lamp is excited with a high-frequency radio frequency (rf) signal. Modulation of the radio frequency signal is used to cause the arc of the HID lamp to selectively operate at an acoustic resonance point. At such a point, the arc undergoes a perturbation and is physically displaced from its quiescent position. When the lamp is placed at a focal or light-gathering point of an optical system having forward gain, displacement of the arc away from the focal point causes discernible changes in the far-field output of the optical system.