Abstract: A refillable plasma cell for use in a laser-sustained plasma light source includes a plasma bulb, the bulb being formed from a glass material substantially transparent to a selected wavelength of radiation, and a gas port assembly, the gas port assembly being operably connected to the bulb and disposed at a first portion of the gas bulb, wherein the bulb is configured to selectively receive a gas from a gas source via the gas port assembly.

Abstract: A high pressure sodium arc tube assembly includes a light-transmitting arc tube containing a fill material including sodium and mercury, a pair of electrodes sealed in opposite ends of the arc tube, and a filament or other resisitive member located within the arc tube and extending between opposite ends thereof. The filament is electrically connected to the electrodes. The filament provides a sufficient electric field and an abundance of electrons dispersed throughout the discharge region to initiate an arc discharge when the electrodes are energized. The filament is selected to produce an electric field in the discharge region prior to initiation of arc discharge of at least 20 volts per centimeter. After an arc discharge is initiated, the voltage between the electrodes drops, and the filament is partially short-circuited by the arc discharge. The filament provides fast initial starting and fast hot restarting, while eliminating the requirement for high voltage starting pulses.