Semiconductor Laser Based Low Power Ammonia Sensors for Remote, Unattended Agricultural Applications

Optical absorption based ammonia sensors have made significant impact in the detection of ammonia in semiconductor fablines and environmental monitoring. Both of these applications require ultrahigh sensitivity of 100 ppt (parts per trillion) and high interference rejection capability for unambiguous identification of trace ammonia in the sampled gases. Also, these applications are relatively insensitive to the sensor weight, sensor dimensions and sensor power consumption since in these applications, sensors are used in a stationary configuration where line electrical power is available.