Nucleic acid amplification techniques have been among the most powerful tools for biological and biomedical research, and the vast majority of the bioassays rely on thermocycling that uses time-consuming and expensive Peltier-block heating. Here, we introduce a plasmonic photothermal method for quantitative real-time PCR, using gold bipyramids and light to achieve ultrafast thermocyding. Moreover, we successfully extend our photothermal system to other biological assays, such 'as isothermal nucleic acid amplification and restriction enzyme digestion.