Laser power meter for pyroelectric, silicon, and thermopile probes. Radiometry, total laser power (cw and average), and irradiance measurements from UV to far-IR, pW to kW, depending on sensor. Resolution 0.005% with RkP probes, 0.03% with other probes. 0.5% accuracy. Integrated lock-in amplifier circuitry for synchronous detection of chopped optical signals, improving both S/N ratio and background rejection. An IEEE-488 GPIB interface, analog outputs, background cancel, autorange, and backlit LCD display are standard features.