A sensor includes an InGaAs photodetector configured to convert received infrared radiation into electrical signals. A notch filter is operatively connected to the InGaAs photodetector to block detection of wavelengths within at least one predetermined band. An imaging camera system includes an InGaAs photodetector configured to convert received infrared radiation into electrical signals, the InGaAs photodetector including an array of photodetector pixels each configured to convert infrared radiation into electrical signals for imaging. At least one optical element is optically coupled to the InGaAs photodetector to focus an image on the array. A notch filter is operatively connected to the InGaAs photodetector to block detection of wavelengths within at least one predetermined band. A ROIC is operatively connected to the array to condition electrical signals from the array for imaging.

A temperature sensing apparatus configured to measure a temperature distribution of a surface to be measured is provided. The temperature sensing apparatus includes a lens set, a filtering module, a plurality of sensor arrays, and a processing unit. The lens set is configured to receive radiation from the surface to be measured. The filtering module is configured to filter the radiation from the lens set into a plurality of radiation portions respectively having different wavelengths. The sensor arrays are configured to respectively sense the radiation portions. The processing unit is configured to calculate an intensity ratio distribution of the radiation between the different wavelengths according to the radiation portions respectively sensed by the sensor arrays and determine the temperature distribution according to the intensity ratio distribution. A laser processing system and a temperature measuring method are also provided.