Tunable microwave cavity

A light source including:

• a. a source of power at a high frequency,
• b. a tunable cavity coupled to the source and having,
• 1. a main cavity having an aperture formed in the wall thereof, and
• 2. an adjustable coupling probe assembly for coupling power to the main cavity and for accurately adjusting the penetration of the probe within the aperture of the cavity wall, the assembly having
• a. a first conductive tube being rigidly affixed to the cavity wall so as to surround the aperture so that a channel is formed from the interior of the tube to the interior of the cavity,
• b. a second conductive tube in movable telescoping relationship with the first conductive tube, the conductive tubes having mutually engaging threads so that the telescoping action occurs in response to rotating the second tube with respect to the first tube, the second tube having inner dimensions which are larger than the outer dimensions of the first tube so tht the second tube is disposed over the outer end of the first tube and wherein the first and second tubes have external and internal mutually engaging threads, respectively,
• c. a power coupling assembly having inner and outer conductors which are fixed with respect to each other, the outer conductor being mounted within the outer end of the second tube so as to conductively contact the second tube,
• d. a coupling probe affixed to the end of the inner conductor and having a length such that the end of the probe may penetrate the main cavity in response to the telescoping effect of the conductive tubes,
• e. means for inhibiting a rotation of the power coupling assembly in response to a rotation of the second conductive tube and for maintaining electrical contact between the outer conductor of the power coupling assembly and the second conductive tube, the rotation inhibiting means including a bearing assembly disposed between the outer conductor and the second tube to permit rotation of the second tube without a corresponding rotation of the power coupling assembly, and
• c. an electrodeless lamp positioned in the main cavity and having an envelope made of a light transmitting material and a volatile fill material disposed within the envelope, the fill material emitting light upon vaporization and excitation.