Here I will report the interaction of light with maters, especially with phonons. I will show three examples including: 1) Raman scattering in 2D layer materials. I will show hoe to use Raman scattering to detect the phonon vibration in 2D materials from bulk to monolayer scale such as interlayer and intralyer vibration in topological insulator、graphene and non-graphene 2D crystals. 2) Laser cooling in semiconductors, i.e. how to use photon to remove the heat (phonon) from materials. By using of strong coupling between excitons and longitudinal optical phonons (LOPs), we not only can cool the whole semiconductor sample from room temperature by 40 Kelvin, but also can selectively cool one specific LO phonon down to quantum ground state. 3) Plasmonic based biosensing. In this part I will show how to use surface enhanced Raman spectroscopy to sensitively detect bio-molecules. It includes our several recent achievements in the development of LSPR nanosensors based on colorimetry, single and arrayed nanoparticle spectroscopy for the detections of several cancer biomarkers.