With increased pressure tungsten has a higher melting point. (source below page 30) 45kBar increases melting point from 3422oC to 3700oC. http://www.nist.gov/data/PDFfiles/jpcrd55.pdf [Broken] An ideal 5800 K black-body, truncated would be 37% efficient. http://en.wikipedia.org/wiki/Luminous_efficacy#Examples So extrapolating this graph a 300kBar light bulb would be at 5800k and 37% efficient. I know this an extremely high pressure but would this theoretically work?