Chinese Academy of Sciences

Juncheng Cao

Zhiyong Tan

Hua Li

Zhen Biao Chen

Li Jun Gu

Ziping Li

Yingjun Han

Yonghao Zhu

Wenjian Wan

The present application provides a terahertz spectrum measurement system and a method for analyzing a terahertz spectrum of a substance, wherein the terahertz spectrum measurement system comprises: two terahertz quantum cascade lasers with their emission ports arranged oppositely; and a vacuum hood arranged between the emission ports of two terahertz quantum cascade lasers. The terahertz spectrum measurement system and the method for analyzing a terahertz spectrum of a substance realize a separate terahertz dual frequency comb while retaining the advantages of the on-chip dual frequency comb system, which solves the problem that the on-chip dual frequency comb cannot directly measure the terahertz spectra of substances.

Terahertz spectrum measurement system and method for analyzing a terahertz spectrum of a substance

A calibration method for an absolute responsivity of a terahertz quantum well detector and a calibration device thereof, in which the device at least comprises: a driving power supply, a single frequency laser source, an optic, a terahertz array detector, a terahertz dynamometer, a current amplifier and an oscilloscope. The calibration method adopts a power detectable single frequency laser source as a calibration photosource, to obtain the absolute responsivity parameters of the detector at the laser frequency; a normalized photocurrent spectrum of the detector is used to further calculate the absolute responsivity parameters of the detector at any detectable frequency. the single frequency laser source with periodically output is adopted as a calibration photosource, the terahertz array detector and the dynamometer are adopted to directly measure and obtain the incident power of the calibrated detector.

Method for calibrating absolute responsivity of terahertz quantum well detector and device thereof

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.

Apparatus and method of power measurement for pulsed terahertz quantum-cascade laser

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Shanghai, China

Juncheng Cao