Computer games wouldn't be the same without the joystick; music and movies on CDs and DVDs wouldn't exist without the pickup mechanism. The world's top audio cartridge for playing vinyl records and high-powered microscopes that can take still photographs of living cells. At the core of these devices is optical technology that utilizes the principles of light. In this episode of J-TECH we meet a Japanese theoretical physicist who has focused his career on developing products that contribute to our health and wellbeing by harnessing the power of light.