How do you build a pico laser?

Building a pico laser involves several key components: a laser gain medium (like a solid-state crystal), a pump source (such as a diode laser), and an optical cavity formed by mirrors. The gain medium is excited by the pump source, causing it to emit photons that are amplified as they bounce between the mirrors, producing a coherent light beam. Additionally, precise control systems for temperature and alignment are necessary to ensure optimal performance. Due to the complexity and safety concerns of lasers, constructing one typically requires advanced knowledge in optics and engineering.