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Power measuring device and method for continuous mass terahertz quantum cascade laser

A quantum cascade and power measurement technology, applied in the terahertz field, can solve problems such as inconvenient, difficult to apply widely, inconvenient use process, etc., to achieve the effect of easy installation and testing, and high collection efficiency

Active Publication Date: 2013-12-18
SHANGHAI INST OF MICROSYSTEM & INFORMATION TECH CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Since the repetition frequency of the pulsed terahertz quantum cascade laser output laser is usually about 5kHz (corresponding to 0.2 milliseconds), and the time constant of ordinary thermal detectors (such as Golay Cell) is usually about 20 milliseconds, the common It is difficult to measure the output laser power of pulsed terahertz quantum cascade lasers with thermal detectors
Currently, liquid helium Dewar-cooled bolometer detectors and room temperature Golay Cell detectors are mainly used to measure the output power of CW-type terahertz quantum cascade lasers in the world, but they are very expensive and difficult to be widely used.
In addition, the use of the bolometer detector requires a complete set of liquid helium transmission system, the measurement process takes a long time, and the use process is inconvenient and not fast

Method used

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  • Power measuring device and method for continuous mass terahertz quantum cascade laser
  • Power measuring device and method for continuous mass terahertz quantum cascade laser
  • Power measuring device and method for continuous mass terahertz quantum cascade laser

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Experimental program
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Effect test

Embodiment 1

[0034] This embodiment provides a power measurement device for a CW type terahertz quantum cascade laser, such as figure 1 shown.

[0035] The device includes a light source part A, an optical path part B and a detection part C.

[0036] 【Light source part A】

[0037] The light source part A includes: a cold head 1, a heat sink 2 installed in the cold head 1, a terahertz quantum cascade laser installed on the heat sink 2, and a polyethylene window 3; the polyethylene window 3 Installed on the cold head 1 so that the terahertz light emitted by the terahertz quantum cascade laser is emitted through the polyethylene window 3 .

[0038] Wherein, the heat sink is made of copper material, which is commonly used in heat conductors of micro devices in the field of low temperature technology. The active region of the terahertz quantum cascade laser is a "four-well resonant phonon" structure, and GaAs / Al is alternately grown on a semi-insulating GaAs substrate by molecular beam epita...

Embodiment 2

[0047] What this embodiment describes is the measuring method of the measuring device described in Embodiment 1, comprising the following steps:

[0048] Step 1, apply a square wave voltage signal with a period of 4s to the terahertz quantum cascade laser installed on the heat sink of the light source part (see Figure 4 ), the terahertz quantum cascade laser radiates terahertz light (frequency 4.13THz) with a period of 4s. Terahertz light with periodic changes reaches the first off-axis parabolic mirror 4 after passing through the polyethylene window.

[0049] Step 2, the first off-axis parabolic mirror receives the terahertz light emitted through the polyethylene window, and reflects the terahertz light to the second off-axis parabola; the second off-axis parabola receives the terahertz light The terahertz light reflected by the first off-axis parabolic mirror, and the terahertz light is reflected to the sensitive surface of the thermal detector of the detection part;

[0...

Embodiment 3

[0053] In this embodiment, the collection efficiency of the measuring device described in Embodiment 1 is detected, and there are four parts to be detected:

[0054] (1) The transmittance of the polyethylene window of the cold head to 4.13THz light;

[0055] (2) The collection efficiency of the first off-axis parabolic mirror to the terahertz light emitted by the polyethylene window;

[0056] (3) Reflection efficiency of the first off-axis parabolic mirror and the second off-axis parabolic mirror to 4.13THz light;

[0057] (4) The transmittance of the atmosphere in the entire optical path to 4.13THz light.

[0058] The experimental measurement results obtained by taking the collection efficiency of 4.13THz light as an example are as follows:

[0059] (1) The transmittance of the polyethylene window installed on the cold head is 56%;

[0060] (2) The collection efficiency of the first off-axis parabolic mirror to 4.13THz light is 10%;

[0061] (3) The reflectivity of the tw...

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Abstract

The invention discloses a power measuring device and a power measuring method for a continuous mass terahertz quantum cascade laser. The device comprises a light source part, a light path part and a probing part, wherein the light source part comprises a cold junction, a heat sink arranged in the cold junction, a terahertz quantum cascade laser arranged on the heat sink and a polythene window sheet which is arranged on the cold junction and is used for emitting terahertz light; the light path part comprises a first off-axis parabolic mirror and a second off-axis parabolic mirror, the first off-axis parabolic mirror collects the terahertz light emitted by the polythene window sheet, and the second off-axis parabolic mirror receives the terahertz light reflected by the first off-axis parabolic mirror; the probing part comprises a heat probe and an oscillometer; the heat probe receives the terahertz light reflected by the second off-axis parabolic mirror and generates a corresponding voltage signal; and the oscillometer extracts and displays the voltage signal to acquire the amplitude of the voltage signal. The light path part and the probing part can perform measurement at normal temperature, so that the power measuring device is convenient to install and measure.

Description

technical field [0001] The invention belongs to the technical field of terahertz, and relates to a power measurement device and method of a continuous lasing type terahertz quantum cascade laser. Background technique [0002] Terahertz (THz, 1THz=10 12 Hz) band refers to a section of electromagnetic wave region with a frequency between infrared and millimeter waves, which is called "THz gap". In recent years, THz technology and its applications have developed rapidly. As an important radiation source in the THz band, Terahertz Quantum Cascade Lasers (THz QCLs) have been extensively and deeply studied, and important progress has been made. It has the characteristics of high energy conversion efficiency, small size, easy integration and long service life. So far, the highest operating temperature of THz QCLs is 186K in pulse mode and 117K in continuous mode; under the optimal working conditions, its highest output power can reach 248mW (pulse mode) and 130mW (continuous mode...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G01J1/42G01J1/04
Inventor 谭智勇曹俊诚黎华郭旭光韩英军
Owner SHANGHAI INST OF MICROSYSTEM & INFORMATION TECH CHINESE ACAD OF SCI