Dear Danmin Chen,

You may want to review the following data:

https://www.omega.com/en-us/temperature-measurement/noncontact-temperature-measurement/fixed-infrared-temperature-sensors/osat/p/OSAT-151-C-MT-05?gclsrc=aw.ds&gclid=Cj0KCQjww4OMBhCUARIsAILndv5fR18A0ynO1NrR5wM8QuJLrUjyjJiafTQHXqL0AHV1KwnHvUblS9EaAl_NEALw_wcB

https://www.omega.com/en-us/temperature-measurement/noncontact-temperature-measurement/handheld-infrared-industrial-thermometers/os758-ls-series/p/OS758-LS?gclsrc=aw.ds&gclid=CjwKCAjwoP6LBhBlEiwAvCcthPopgLD4MnO-IdaSGKB4OSxgN7Ewmci76pMRjxwsDYDsyUsljskUYRoCj1cQAvD_BwE

https://www.omega.com/en-us/temperature-measurement/noncontact-temperature-measurement/handheld-infrared-industrial-thermometers/os-vir50-series/p/OS-VIR50?gclsrc=aw.ds&gclid=Cj0KCQjww4OMBhCUARIsAILndv44G7tVCsnn_l-MguM2Ktx4S2HWpPze8PIrYRZqL6KF5Ak_sjzKqcUaAntOEALw_wcB

https://www.osapublishing.org/josa/abstract.cfm?uri=josa-13-1-117

https://www.globalspec.com/ds/111/areaspec/tech_thermal_based

https://www.quora.com/What-are-the-thermometers-used-to-measure-very-high-temperature

Hi Dr Danmin Chen . See the following link: https://www.micro-epsilon.com/download/manuals/man--thermoMETER-CTVideo--en.pdf

See the following link: https://www.digitalcameraworld.com/buying-guides/best-infrared-thermometer

Also see the following link : https://www.weatherstationadvisor.com/best-infrared-thermometer-reviews/

Kindly see also the following link: https://www.bobvila.com/articles/best-infrared-thermometer/