Patent ID: 8749225

Claim:
A power measurement apparatus for a pulsed terahertz quantum-cascade laser (THz QCL), comprising: a light source part (A), a light path part (B) and a detection part (C), wherein the light source part (A) comprises a first cold head ( 2 ), a first heat sink ( 3 ) mounted in the first cold head ( 2 ), a THz QCL mounted on the first heat sink ( 3 ), a pulse power supply ( 1 ) connected to the THz QCL, and a first polyethylene window ( 4 ) mounted on the first cold head; terahertz light emitted by the THz QCL is emitted to the outside through the first polyethylene window ( 4 ); the light path part (B) comprises a first off-axis parabolic mirror ( 5 ) and a second off-axis parabolic mirror ( 6 ); the first off-axis parabolic mirror ( 5 ) collects the terahertz light emitted to the outside through the first polyethylene window ( 4 ), and reflects the terahertz light to the second off-axis parabolic mirror ( 6 ); the second off-axis parabolic mirror ( 6 ) receives the terahertz light reflected by the first off-axis parabolic mirror ( 5 ), and reflects the terahertz light to the detection part (C); and the detection part (C) comprises a second cold head ( 7 ), a second polyethylene window ( 8 ) mounted on the second cold head ( 7 ), a second heat sink ( 9 ) mounted in the second cold head ( 7 ), a terahertz quantum-well photodetector (THz QWP) mounted on the second heat sink ( 9 ), a signal processing circuit ( 10 ) connected to the THz QWP, and an oscilloscope ( 11 ) connected to the signal processing circuit ( 10 ); the second polyethylene window ( 8 ) enables the terahertz light reflected by the second off-axis parabolic mirror ( 6 ) to enter the second cold head ( 7 ) and reach the sensitive surface of the THz QWP; the THz QWP is used to receive the terahertz light reflected by the second off-axis parabolic mirror ( 6 ), and generate a corresponding current signal; the signal processing circuit ( 10 ) extracts out a voltage signal from the current signal, and amplifies the voltage signal; the oscilloscope ( 11 ) is used to read and display the voltage signal amplified by the signal processing circuit ( 10 ), so as to acquire the amplitude of the voltage signal.