| 摘要 |
The present invention provides a power measurement apparatus and method for a pulsed terahertz quantum-cascade laser (THz QCL). The apparatus includes a light source part, a light path part, and a detection part. Terahertz light emitted by a THz QCL reaches a terahertz quantum-well photodetector (THz QWP) through the measurement apparatus, and is absorbed to generate a corresponding current signal. A signal processing circuit extracts a voltage signal from the current signal, amplifies the voltage signal, and inputs the amplified voltage signal to an oscilloscope for reading and displaying. According to a responsivity of the THz QWP at a lasing frequency of the laser, the measurement of the output power of the pulsed THz QCL is acquired. The present invention avoids integration estimation when a thermal detector is used to measure output power of a THz QCL in a pulse operating mode, and can directly acquire the power value of a pulsed output from the laser according to the amplitude of the detector responding to the pulsed terahertz light. |
| 主权项 |
1. 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.
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