| 摘要 |
PROBLEM TO BE SOLVED: To provide a sensor that implements reduction in device size and eliminates the need of considering moisture in the air, to dispense with nitrogen filling work between devices.SOLUTION: A sensor 1 includes an input unit 11 which inputs electromagnetic waves of two frequencies f1 and f2, a secondary nonlinear optical crystal 12 to which the electromagnetic waves are input, a detection target installation area 13 provided in the range of oozing length of an evanescent component of frequency f3=|f1-f2| of the nonlinear optical crystal 12, and a detection unit 14 which is provided in an area different from the detection target installation area 13 and near the surface of the nonlinear optical crystal 12. |
