Our group studies the mutual interaction of heat, light, and electricity in nano and microscale materials and devices. We use this mutual interaction to improve device performance either in energy conversion or in information processing applications. For example, we have designed micro refrigerators on a chip that could be used to remove hot spots in microprocessor chips. We have also developed novel AC imaging techniques to obtain thermal maps of active devices with submicron spatial resolution and microsecond time resolution. We are applying similar techniques to improve imaging in turbid media using ultrafase lasers. In a major multi-university research initiative, we are working to achieve high efficiency and high power density direct thermal to electric energy conversion. By using embedded metallic nanoparticles and multilayers for hot electron filtering and thermal conductivity reduction, we improve the intrinsic thermoelectric properties of the material.