阅读说明：本技术 一种基于高压气体膨胀降温激发的太赫兹激光器 (Terahertz laser based on high-pressure gas expansion cooling excitation ) 是由 黄海涛 欧阳征标 黄粤龙 林密 于 2020-03-04 设计创作，主要内容包括：本发明公开了一种基于高压气体膨胀降温激发的太赫兹激光器,包括：储藏容器,用于在恒温恒压状态下存储工作物质,所述储藏容器的输出口连接输送管；膨胀腔,通过所述输送管与所述储藏容器相连,所述工作物质经输送管输送到膨胀腔中进行膨胀,产生太赫兹辐射；谐振腔,所述膨胀腔的两端壁上均设有透明窗,并在两个所述透明窗外分别设有共轴的高反射镜和部分反射镜,形成谐振腔；所述太赫兹辐射经所述谐振腔的协同形成太赫兹激光。本发明的太赫兹激光器具有高效率、成本低和体积小的特点。(The invention discloses a terahertz laser based on high-pressure gas expansion cooling excitation, which comprises: the storage container is used for storing working substances in a constant-temperature and constant-pressure state, and an output port of the storage container is connected with the conveying pipe; the expansion cavity is connected with the storage container through the conveying pipe, and the working substance is conveyed into the expansion cavity through the conveying pipe to be expanded so as to generate terahertz radiation; transparent windows are arranged on two end walls of the expansion cavity, and coaxial high reflectors and partial reflectors are arranged outside the two transparent windows respectively to form a resonant cavity; and the terahertz radiation is coordinated by the resonant cavity to form terahertz laser. The terahertz laser has the characteristics of high efficiency, low cost and small volume.)

1. The utility model provides a terahertz laser based on high-pressure gas inflation cooling arouses which characterized in that includes:

the storage container is used for storing the working substance under the constant temperature and pressure state, and an output port of the storage container is connected with the conveying pipe;

the expansion cavity is connected with the storage container through the conveying pipe, and the working substance is conveyed into the expansion cavity through the conveying pipe to be expanded so as to generate terahertz radiation;

a first transparent window and a second transparent window are respectively arranged on two end walls of the expansion cavity, and a coaxial high reflector and a coaxial partial reflector are respectively arranged outside the first transparent window and the second transparent window to form a resonant cavity; and the terahertz radiation is coordinated by the resonant cavity to form terahertz laser.

2. The terahertz laser based on high-pressure gas expansion cooling excitation according to claim 1, wherein a constant temperature and pressure control system is connected to the storage container to adjust the constant temperature and pressure in the storage container, so as to adjust the output frequency of the terahertz laser.

3. The terahertz laser based on high-pressure gas expansion cooling excitation according to claim 2, wherein heat is supplied to the storage container heat supply source through a heat supply source, and the heat supply source is generated from one of combustible gas, combustible liquid, combustible solid or an external heater.

4. The terahertz laser based on high-pressure gas expansion cooling excitation according to claim 3, wherein the temperature of the heat supply source is 0.1-600 ℃.

5. The terahertz laser based on high-pressure gas expansion cooling excitation of claim 4, wherein a pressure reducing valve and a throttle valve are arranged on the delivery pipe, the pressure reducing valve and the throttle valve are connected with a power frequency control system, and the flow and the pressure of the throttle valve and the pressure reducing valve are controlled by the power frequency control system to realize the adjustment of the output power of the terahertz laser.

6. The terahertz laser based on high-pressure gas expansion cooling excitation according to claim 5, wherein the power frequency control system is connected with the high reflector and the partial reflector to control the distance between the high reflector and the partial reflector so as to adjust the output frequency of the terahertz laser; the first transparent window and the high reflecting mirror are positioned on the end wall of the expansion cavity or are replaced by the high reflecting mirror and are arranged at the position of the first transparent window on the end wall of the expansion cavity; and the second transparent window and the partial reflector or the partial reflector which are positioned on the end wall of the expansion cavity are replaced by the partial reflector and are arranged at the position of the second transparent window on the end wall of the expansion cavity.

7. The terahertz laser based on high-pressure gas expansion cooling excitation according to claim 6, wherein the high-reflection mirror and the partial reflection mirror are metal or dielectric mirrors, the reflectivity of the high-reflection mirror to terahertz waves is 90% to 100%, and the transmittance of the high-reflection mirror is 0; the partial reflector has 90-99% of terahertz wave pair reflectivity and 1-10% of transmissivity; and the equivalent optical distance between the high reflector and the partial reflector is integral multiple of half wavelength of working terahertz wave.

8. The terahertz laser based on high-pressure gas expansion cooling excitation of claim 7, further comprising a working parameter display system connected to the power frequency control system and the constant temperature and pressure control system, and configured to receive the collected parameters of the power frequency control system and the constant temperature and pressure control system for display, calculate and output working parameters of the terahertz laser according to the collected parameters, and display the working parameters.

9. The terahertz laser based on high-pressure gas expansion cooling excitation according to claim 8, wherein the frequency of the output terahertz laser is between 0.1THz and 30 THz.

10. The terahertz laser based on high-pressure gas expansion cooling excitation according to claim 1, wherein the working substance is one or a mixture of organic gas, organic liquid, inorganic gas and inorganic liquid.

Technical Field

The invention relates to the technical field of terahertz, in particular to a terahertz laser based on high-pressure gas expansion cooling excitation.

Background

Terahertz technology has wide applications in communication, sensing, remote sensing, security, drug detection, medical treatment, radar and the like, and has been widely regarded in recent years. All terahertz technologies and applications are not separable from terahertz sources.

At present, terahertz sources based on electronic technology frequency up-conversion, vacuum technology free electronic devices, semiconductor technology quantum cascade devices and optical down-conversion technology have the problems of extremely low efficiency and high cost, and most of the sources have large volumes, so that the terahertz sources with high efficiency, low cost and small volume become the problems which are urgently needed to be solved at present.

Disclosure of Invention

In order to overcome the defects of the prior art, the invention aims to provide the terahertz laser based on high-pressure gas expansion cooling excitation, which can improve the output efficiency of terahertz laser and has the characteristics of small volume and low cost.

The purpose of the invention is realized by adopting the following technical scheme:

a terahertz laser based on high-pressure gas expansion cooling excitation comprises:

the storage container is used for storing the working substance under the constant temperature and pressure state, and an output port of the storage container is connected with the conveying pipe;

the expansion cavity is connected with the storage container through the conveying pipe, and the working substance is conveyed into the expansion cavity through the conveying pipe to be expanded so as to generate terahertz radiation;

a first transparent window and a second transparent window are respectively arranged on two end walls of the expansion cavity, and a coaxial high reflector and a partial reflector are respectively arranged outside the first transparent window and the second transparent window to form a resonant cavity; and the terahertz radiation is coordinated by the resonant cavity to form terahertz laser.

Furthermore, the storage container is connected with a constant temperature and pressure control system to adjust the constant temperature and pressure of the storage container, so that the output frequency of the terahertz laser can be adjusted.

Further, heat is provided for the storage container heat supply source through a heat supply source, wherein the heat supply source is generated from one of combustible gas, combustible liquid, combustible solid or an external heater.

Further, the temperature of the heat supply source is 0.1 to 600 ℃.

Furthermore, a pressure reducing valve and a throttle valve are arranged on the conveying pipe, the pressure reducing valve and the throttle valve are connected with a power frequency control system, and the power frequency control system controls the flow and the pressure of the throttle valve and the pressure reducing valve to adjust the output power of the terahertz laser.

Further, the power frequency control system is connected with the high reflecting mirror and the partial reflecting mirror to control the distance between the high reflecting mirror and the partial reflecting mirror and realize the adjustment of the output frequency of the terahertz laser; the first transparent window and the high reflecting mirror are positioned on the end wall of the expansion cavity or are replaced by the high reflecting mirror and are arranged at the position of the first transparent window on the end wall of the expansion cavity; and the second transparent window and the partial reflector or the partial reflector which are positioned on the end wall of the expansion cavity are replaced by the partial reflector and are arranged at the position of the second transparent window on the end wall of the expansion cavity.

Furthermore, the high reflector and the partial reflector are metal or medium reflectors, the reflectivity of the high reflector to the terahertz wave is 90% -100%, and the transmissivity of the high reflector is 0; the partial reflector has 90-99% of terahertz wave pair reflectivity and 1-10% of transmissivity; and the equivalent optical distance between the high reflector and the partial reflector is integral multiple of half wavelength of working terahertz wave.

Furthermore, the terahertz laser also comprises a working parameter display system which is connected with the power frequency control system and the constant temperature and constant pressure control system and used for receiving the acquisition parameters of the power frequency control system and the constant temperature and constant pressure control system, calculating and outputting the working parameters of the terahertz laser according to the acquired parameters and displaying the working parameters.

Further, the frequency of the output terahertz laser is between 0.1THz and 30 THz.

Further, the working substance is one or a mixture of more of organic gas, organic liquid, inorganic gas and inorganic liquid.

Compared with the prior art, the invention has the beneficial effects that:

the terahertz laser disclosed by the invention expands and cools the high-temperature and high-pressure gas by utilizing the vibration and rotational radiation of widely existing molecular atoms or crystal lattices, and during the cooling process, working substance molecules jump from a higher virtual or inherent energy level to a lower virtual or inherent energy level, so that terahertz waves are radiated, the terahertz laser is output by utilizing the synergistic action of the resonant cavity, and the terahertz laser has the characteristics of high efficiency, small volume and low cost.

Drawings

Fig. 1 is a schematic structural diagram of a terahertz laser based on high-pressure gas expansion cooling excitation according to the present invention.

In the figure: 01. a storage container; 011. a working substance; 02. a delivery pipe; 03. a pressure reducing valve; 04. a throttle valve; 05. an expansion chamber; 06. an exhaust pipe; 07. a resonant cavity; 071. a high reflection mirror; 072. a partial mirror; 08. a constant temperature and pressure control system; 09. a power frequency control system; 10. a working parameter display system; 11. and a power supply module.

Detailed Description

The present invention will be further described with reference to the accompanying drawings and the detailed description, and it should be noted that any combination of the embodiments or technical features described below can be used to form a new embodiment without conflict.

The invention provides a terahertz laser which is generated by cooling excitation based on high-pressure gas expansion and has the characteristics of high efficiency, low cost and small volume.

Referring to fig. 1, the laser includes a storage container 01, wherein the storage container 01 is used for storing a working substance 011 in a constant temperature and pressure state; the working substance 011 can be organic or inorganic substance, or a mixture of organic or inorganic substance. Specifically, the organic working substance 011 can be ketones, aldehydes, ethane, propane, butane, pentane, hydrocarbon mixtures, ethylene, propylene, butylene, alkene mixtures, freon, saturated hydrocarbons, unsaturated hydrocarbons, or azeotropic mixtures, etc. The inorganic working substance 011 can be air, carbon dioxide, oxygen, nitrogen, hydrogen, sulfur dioxide, or the like, and specific substances of organic and inorganic substances are not limited herein. Further, the working substance 011 may be liquid or gas, and is not limited thereto.

The constant temperature heat of the storage container 01 can be provided by a heat supply source, and the constant temperature of 0.1-600 ℃ is provided for the storage container 01 by the heat supply source; the heat supply source can be generated from one of combustible gas, combustible liquid, combustible solid or an external heater; the external heater may be a combustion furnace, a resistive electric heater, an electromagnetic induction electric heater, an ultrasonic heater, a radio wave heater, a microwave heater, a far infrared heater, an infrared heater, a near infrared heater, a visible light heater, a solar radiation heater, or a geothermal heater, and supplies sufficient constant temperature heat to the storage container 01 by using alternating current, radio waves, microwaves, far infrared light, near infrared light, visible light, solar radiation, plasma, geothermal heat, or the like, which is generated from the external heater, as a heat supply source.

An output port is formed in the storage container 01, a conveying pipe 02 is connected to the output port of the storage container 01, and the storage container 01 is connected with the expansion cavity 05 through the conveying pipe 02; and the storage container 01 is in a high-pressure high-temperature state, so that the gaseous working substance 011 in the storage container 01 is conveyed into the expansion cavity 05 through the conveying pipe 02, or the gaseous working substance 011 is changed into a gaseous state under the high-temperature high-pressure environment and then conveyed into the expansion cavity 05 through the conveying pipe 02.

Gas with relatively high temperature enters the expansion cavity 05 and then expands to reduce the temperature, and molecules can radiate electromagnetic waves in the molecular vibration, rotation and average molecular motion deceleration processes, wherein the electromagnetic waves comprise terahertz waves.

An exhaust pipe 06 is arranged on the expansion cavity 05, and gas in the expansion cavity 05 can be directly exhausted into the atmosphere or exhausted into a designated container for storage or treatment through the exhaust pipe 06 after being expanded and cooled. In this embodiment, the direction of the airflow in the expansion cavity 05 is perpendicular to the long-side wall of the expansion cavity 05, and the first transparent window and the second transparent window are disposed outside the two short-side walls (i.e., the two end walls) of the expansion cavity 05, and the transparent windows do not absorb or substantially do not absorb the terahertz waves; coaxial high-reflection mirrors 071 and partial reflection mirrors 072 are respectively arranged outside the first transparent window and the second transparent window to form a resonant cavity 07, so that the terahertz radiation is cooperated with the resonant cavity 07 to form terahertz laser.

The equivalent optical distance between the high reflector 071 and the partial reflector 072 is an integral multiple of half wavelength of working terahertz wave, the high reflector 071 and the partial reflector 072 are connected to a power frequency control system 09, and the power frequency control system 09 can control the distance between the high reflector 071 and the partial reflector 072, so as to achieve the purpose of adjusting the output frequency of the terahertz laser; a first transparent window and a high-reflection mirror 071 positioned on the end wall of the expansion cavity 05 or replaced by the high-reflection mirror 071 and arranged at the position of the first transparent window on the end wall of the expansion cavity 05; a second transparent window and partial mirror 072 or a partial mirror 072 located at the end wall of the expansion chamber 05 is replaced and arranged at the position of the second transparent window at the end wall of the expansion chamber 05.

The high reflecting mirror 071 and the partial reflecting mirror 072 can be metal or dielectric reflecting mirrors, the reflectivity of the high reflecting mirror 071 to the terahertz wave is 90% -100%, and the transmissivity thereof is 0; the reflectivity of the partial reflector 072 to terahertz waves is 90% -99%, and the transmissivity of the partial reflector 072 is 1% -10%; the high-reflection mirror 071 and the partial-reflection mirror 072 are coaxial, and the working frequency thereof is between 0.1THz and 30THz, that is, the resonant cavity 07 selects light with consistent frequency and direction between 0.1THz and 30THz to preferentially amplify, and suppresses light with other frequencies and directions, thereby outputting terahertz laser light with the frequency between 0.1THz and 30 THz.

The working principle of the terahertz laser in the embodiment is as follows:

the working substance 011 expands freely in the gas expansion chamber 05, and the amount of decrease in internal energy per molecule is, on average, Δ T relative to the amount of decrease in temperature in the constant-temperature constant-pressure high-pressure gas storage container 01

Wherein k is Boltzmann constant; i is the degree of freedom of the gas molecule. At normal temperature, for monoatomic gas, i is 3; for a rigid diatomic gas, i ═ 5; for rigid polyatomic gases: i 6 and i 3n for elastomeric macromolecules, where n is the number of atoms in each molecule.

Working outwards in the process of gas expansion, and setting the pressure and temperature before expansion as P₁、T₁(working substance molecules are at a virtual or intrinsic energy level E₁) Pressure and temperature after expansion are respectively P₂、T₂(working substance molecules are at a virtual or intrinsic energy level E₂). Since the gas expansion chamber 05 is open to atmosphere, there is P₂＝P₀1 atmosphere.

Since the expansion process is fast, the gas can be considered to have no heat exchange with the outside, i.e. Q is 0, the energy exchange with the outside represents the terahertz radiation and the expansion work, and can be considered to be a multiparty process similar to adiabatic expansion.

The gas state equation for the multi-square process is:

where n is the polytropic index, M is the mass of the gas, M is the molar mass of the gas, and R is 8.31451 J.mol^-1·K^-1Is a universal gas constant. Further, the compounds represented by the formulae (2) and (3) can be obtained

The gas work A is as follows:

internal energy variation can be written as:

wherein the content of the first and second substances,is the molar constant volume heat capacity of the gas.

According to the conservation of energy

-ΔE＝A+Q+E_r, (8)

Since the process proceeds very fast, the heat conduction is negligible, i.e. Q is 0, so the terahertz radiation energy is:

E_r＝-ΔE-A, (9)

further represented by the formula (6,7,9) having

According to the principle of electrodynamic force, the charged particles or the electric dipoles radiate electromagnetic waves when doing acceleration or deceleration motion, so that the molecules radiate electromagnetic waves including terahertz waves in the process of molecular motion deceleration of molecular vibration, rotation and translation with the temperature of the working substance 011 reduced. According to energy conservation, the internal energy reduced quantity is partially converted into terahertz radiation energy, and part of the internal energy reduced quantity is released in the form of heat energy. According to the relation between the radiation energy and the frequency of quantum mechanics and the formula (10), the frequency of the terahertz radiation can be calculated as follows:

where q is the coefficient for generating terahertz radiation quanta. Formula (5) may be substituted for formula (11):

wherein h is 6.62606896 × 10^-34J.s is Planck constant, N_A＝6.02214076×10²³Is the avogalois constant.

As can be seen from equation (12), the terahertz output frequency can be adjusted by adjusting the temperature and pressure of the gas in the constant-temperature constant-pressure high-pressure gas storage container 01. The constant volume molar heat capacity and polytropic index of the gas also affect the terahertz output frequency. The throttle valve 04 is used for adjusting the gas flow, the more molecules participating in radiation in unit time, the higher the radiation power is, and otherwise, the lower the radiation power is.

Since Δ T <0 and the frequency must be greater than zero, it must be satisfied

In this embodiment, the frequency of the terahertz laser output by the terahertz laser can be adjusted by adjusting the constant temperature and pressure of the gas in the storage container 01, in addition to adjusting the distance between the high mirror 071 and the partial mirror 072, so as to change the output frequency of the output terahertz light.

The temperature and pressure of the storage container 01 can be adjusted by a constant temperature and pressure control system 08, and the constant temperature and pressure control system 08 can monitor the temperature and pressure in the storage container 01 in real time, change the pressure in the storage container 01, and change the heat provided by the heat source to the storage container 01.

The power of the terahertz laser output by the terahertz laser can be adjusted through a throttle valve 04 arranged on the conveying pipe 02; a pressure reducing valve 03 and a throttle valve 04 are arranged on the delivery pipe 02, wherein the pressure reducing valve 03 is used for reducing the pressure in the storage container 01 so as to maintain the pressure in the storage container 01 constant; the throttle valve 04 can control the gas flow entering the expansion cavity 05, so that the output power of the terahertz laser is adjusted; the reducing valve 03 and the throttling valve 04 are connected with a power frequency control system 09, the power frequency control system 09 can automatically control the working states of the reducing valve 03 and the throttling valve 04, and the working parameters of the reducing valve 03 and the throttling valve 04 are collected.

In addition, the terahertz laser further comprises a working parameter display system 10, which is connected with the power frequency control system 09 and the constant temperature and pressure control system 08, and is used for receiving the acquisition parameters of the power frequency control system 09 and the constant temperature and pressure control system 08, calculating and outputting the working parameters of the terahertz laser according to the acquired parameters, and displaying the working parameters. The working parameter display system 10 can display parameter values such as power and frequency of the output terahertz laser, temperature and pressure of the working substance 011, ambient temperature and pressure, and power supply voltage.

Meanwhile, the terahertz laser is further provided with a power supply module 11, the power supply module 11 is connected with the power frequency control system 09, the constant temperature and constant voltage control system 08 and other components to provide electric energy for the components, and the power supply module 11 can be an alternating current or direct current power supply with the voltage ranging from 6 volts to 380 volts.

For the terahertz laser of this embodiment, different working substances 011 are used to obtain different output frequencies, and the following tests are performed on the different working substances 011.

Several specific examples are given below: