Continuum visible spectra from InBr discharge excited in a microwave resonant cavity

Emissions from InBr radiation have been investigated in a microwave resonant cavity system. We demonstrate that with proper operation the emission spectra of InBr can be a continuum in the visible range and can be suitable for lighting applications. The continuum spectra are stronger with an increase in input microwave power. In our system, a high color rendering index of 97 can be obtained from the bulb with 25 mg InBr and 800 W input microwave power. The spectral lines 410.1 and 451.1 nm from In I play an important role to balance the spectral distribution for lighting requirements. The continuum spectra may be due to the transition of Rydberg states to the C state of InBr molecules. (C) 2007 American Institute of Physics.