Patent ID: 9739661
Date: 2017-08-22
CPC Classifications: G01J,G01N

Claim:
1. An apparatus comprising: a tunable mid-infrared (MIR) laser that generates a light beam; a specimen stage adapted to carry a specimen to be scanned, said stage moving said specimen in a first direction; an optical assembly that focuses said light beam to a point on said specimen, said optical assembly comprises a scanning assembly having a focusing lens that focuses said light beam to a point on said specimen and a mirror that moves in a second direction relative to said stage such that said focusing lens maintains a fixed distance between said focusing lens and said specimen stage, said first direction being different from said second direction; a first light detector that measures a first intensity of light leaving said point on said specimen; a controller that forms a MIR image from said first intensity of light; and a reference stage that is different from said specimen stage positioned such that said mirror moves over said reference stage in response to a command from said controller, wherein said focusing lens and said mirror move together in said second direction over said specimen stage and said reference stage.