The Keysight 423B Low-Barrier Schottky Diode detector has been widely used for many years in a variety of applications including leveling and power sensing. It offers good performance and ruggedness. Matched pairs (Option 001) offer very good detector tracking. A video load (Option 002) extends the square-law region to at least 0.1 mW (-10 dBm).
HP / Agilent 423B