Broadband terahertz upconversion detector based on alkali noble gas excimer molecules

Abstract

The application provides a wideband terahertz upconversion detector based on alkali metal inert gas quasi-molecule, comprising: a gas cell for containing alkali metal vapor and inert gas, the alkali metal vapor and inert gas naturally form a quasi-molecule in the gas cell, and terahertz light can be transmitted from the outside to the inside of the gas cell; an auxiliary light source for outputting an auxiliary light beam, the auxiliary light beam emitted by the auxiliary light source can be transmitted from the outside to the inside of the gas cell, the auxiliary light beam and the terahertz light jointly induce the quasi-molecule to transition from a ground state to an excited state in the gas cell, and then generate upconversion fluorescence, and the upconversion fluorescence can be transmitted from the inside to the outside of the gas cell; and a camera for shooting the upconversion fluorescence. By using the wideband absorption characteristics of the alkali metal-inert gas quasi-molecule, the application realizes continuous spectrum detection of the terahertz light frequency, and is no longer limited to specific frequency alkali metal atom transition spectral lines, thereby having universality.

Description

Technical Field

[0001] This invention relates to the field of terahertz optical detection technology, and more particularly to a broadband terahertz upconversion detector based on alkali metal inert gas excimers. Background Technology

[0002] Using Rydberg state alkali metal atoms to detect terahertz light is an emerging terahertz light imaging and detection scheme with advantages such as full-field imaging and high-speed imaging.

[0003] Since its initial report by KJ Weatherill's group at Durham University in 2016 (Nature Photonics doi:10.1038 / NPHOTON.2016.214), alkali metal terahertz detectors have attracted widespread interest. However, Rydberg state alkali metal atom detectors have a significant limitation: using selected alkali metal energy levels, they can only detect specific terahertz frequencies. The accompanying terahertz light source must also be precisely tuned to that frequency; otherwise, imaging failure will occur. This severely restricts their widespread application and urgently needs to be addressed. Summary of the Invention

[0004] To overcome the shortcomings of existing technologies, this invention provides a sensitive broadband terahertz upconversion detector based on alkali metal inert gas excimers. This invention primarily utilizes the broadband absorption characteristics of alkali metal-inert gas excimers to achieve continuous spectrum detection of terahertz light frequencies, no longer limited to specific alkali metal atomic transition lines, thus possessing versatility.

[0005] The technical means employed in this invention are as follows:

[0006] A broadband terahertz upconversion detector based on alkali metal inert gas excimers, comprising:

[0007] A gas pool for holding alkali metal vapor and inert gas, wherein the alkali metal vapor and inert gas naturally form excimers within the gas pool, and terahertz light can be transmitted from the outside of the gas pool to the inside.

[0008] An auxiliary light source is used to output an auxiliary beam. The auxiliary beam emitted by the auxiliary light source can be transmitted from the outside of the gas cell to the inside. The auxiliary beam and the terahertz light together induce the excimer to transition from the ground state to the excited state in the gas cell, thereby generating upconversion fluorescence. The upconversion fluorescence can be transmitted from the inside of the gas cell to the outside.

[0009] A camera used to capture the upconversion fluorescence.

[0010] Furthermore, the terahertz light frequency is in the range of 0.5THz to 10THz.

[0011] Furthermore, the gas cell is made of Sapphire, the terahertz light frequency is in the range of 0.5-3 THz, the alkali metal vapor is cesium vapor, the inert gas is argon, the auxiliary beam wavelength is 841 nm, and the upconversion fluorescence wavelength is 852 nm.

[0012] Furthermore, the gas cell is made of Sapphire, the terahertz light frequency is in the range of 0.5-3 THz, the alkali metal vapor is cesium vapor, the inert gas is argon, the auxiliary beam wavelength is 830 nm, and the upconversion fluorescence wavelength is 852 nm.

[0013] Furthermore, the gas cell is made of Sapphire, the terahertz light frequency is in the range of 0.5-3 THz, the alkali metal vapor is rubidium vapor, the inert gas is helium, the auxiliary beam wavelength is 783 nm, and the upconversion fluorescence wavelength is 780-795 nm.

[0014] Furthermore, the gas cell is made of Sapphire, the terahertz light frequency is in the range of 0.5-3 THz, the alkali metal vapor is rubidium vapor, the inert gas is helium, the auxiliary beam wavelength is 776 nm, and the upconversion fluorescence wavelength is 780-795 nm.

[0015] Furthermore, the gas cell is made of Sapphire, the terahertz light frequency is in the range of 0.5-3 THz, the alkali metal vapor is cesium vapor, the inert gas is helium, the auxiliary beam wavelength is 454 nm, and the upconversion fluorescence wavelength is 455 nm.

[0016] Furthermore, the alkali metal vapor is one or more of lithium vapor, sodium vapor, potassium vapor, rubidium vapor, and cesium vapor.

[0017] Furthermore, the inert gas is one or more of helium, neon, argon, krypton, and xenon.

[0018] Furthermore, the auxiliary light source emits an auxiliary beam with one or more discrete wavelengths, wherein at least one active wavelength is capable of co-inducing excimer energy level transitions with the terahertz light to be detected.

[0019] Compared with the prior art, the present invention has the following advantages:

[0020] The sensitive broadband terahertz upconversion detector based on alkali metal inert gas excimers disclosed in this invention, during operation, forms alkali metal-inert gas excimers with alkali metal and inert gas atoms in the gas cell. Under the combined action of the auxiliary beam and the terahertz light to be measured, the excimer energy level transitions occur, thereby generating a light wave frequency different from that of the auxiliary beam and the terahertz light to be measured, i.e., the light wave frequency of the upconversion fluorescence. This light wave frequency can be sensitively captured by a camera, thereby obtaining an upconversion fluorescence image consistent with the terahertz light field distribution region, thus realizing the terahertz light upconversion imaging detection function. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a schematic diagram of the broadband terahertz upconversion detector based on alkali metal inert gas excimers of the present invention.

[0023] Figure 2 This is a schematic diagram of Embodiment 1 of the present invention.

[0024] Figure 3 This is a schematic diagram of Embodiment 2 of the present invention.

[0025] In the diagram: 1. Gas cell; 2. Auxiliary light source; 3. Auxiliary beam; 4. Camera; 5. Terahertz light; 6. Upconversion fluorescence. Detailed Implementation

[0026] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0027] like Figure 1As shown, this invention provides a broadband terahertz upconversion detector based on alkali metal inert gas excimers, mainly comprising: a gas cell 1, an auxiliary light source 2, and a camera 4. The gas cell holds alkali metal vapor and inert gas, which naturally form excimers within the gas cell. A terahertz beam 5 can be transmitted from the outside of the gas cell 1 to its interior. The auxiliary light source 2 outputs an auxiliary beam 3, which can also be transmitted from the outside of the gas cell to its interior. The auxiliary beam 3 and the terahertz light 5 together induce the excimers to transition from their ground state to an excited state within the gas cell, thereby generating upconversion fluorescence 6. The upconversion fluorescence 6 can be transmitted from the interior of the gas cell 1 to the outside. The camera 4 is used to capture the upconversion fluorescence 6, and its lens can be configured with a filter group to selectively image the upconversion fluorescence.

[0028] In a preferred embodiment of the present invention, the terahertz light frequency is located in the range of 0.5THz to 10THz.

[0029] In a preferred embodiment of the present invention, the alkali metal vapor is one or more of lithium vapor, sodium vapor, potassium vapor, rubidium vapor, and cesium vapor.

[0030] In a preferred embodiment of the present invention, the inert gas is one or more of helium, neon, argon, krypton, and xenon.

[0031] In a preferred embodiment of the present invention, the auxiliary light beam emitted by the auxiliary light source 2 has one wavelength or multiple discrete wavelengths, wherein at least one active wavelength can co-induce excimer energy level transitions with the terahertz light to be detected.

[0032] The following specific application examples will further illustrate the solution of the present invention.

[0033] Example 1: A Sensitive Broadband Terahertz Upconversion Detector Based on Cs-Ar Excimer

[0034] Detector structure as follows Figure 1 As shown. The auxiliary light source 2 emits an auxiliary beam 3 to illuminate the gas cell 1. The gas cell 1 is made of Sapphire material and is transparent to both the 5-terahertz light to be measured and the auxiliary beam 3, as well as to the upconversion fluorescence 6 to be generated. A small amount of metallic cesium (Cs) is filled into the gas cell 1 to generate cesium vapor, while high-purity argon (Ar) is simultaneously filled to 1 atmosphere. At this point, Cs-Ar excimers are generated in the gas cell 1. The permissible wavelength range for the terahertz light 5 is 0.5-3 THz, and this preferred wavelength range is determined based on the transmittance of the gas cell material. The wavelength of the auxiliary beam 3 is... The transition absorbs the red boundary at approximately 841 nm, which, together with terahertz light, induces energy level transitions in Cs-Ar excimers, such as... Figure 2As shown, the combined energy of photons from one auxiliary beam 3 and one terahertz beam 5 triggers... A transition, as indicated by the upward arrow. Because... In a repulsive state, it will rapidly dissociate into argon atoms and atoms located at 6... 2 P 3 / 2 Cesium atoms, located at 6 2 P 3 / 2 Cesium atoms transition to the ground state, producing 852 nm fluorescence, which is the upconversion fluorescence 6, as shown by the downward arrow. It reflects the light field distribution of terahertz light 5 illuminating gas cell 1. The upconversion fluorescence 6 is transmitted out of gas cell 1 and captured by a 4-camera, thus realizing the function of terahertz upconversion detection.

[0035] Example 2: Another sensitive broadband terahertz upconversion detector based on Cs-Ar excimer

[0036] Detector structure as follows Figure 1 As shown. The auxiliary light source 2 emits an auxiliary beam 3 to illuminate the gas cell 1. The gas cell 1 is made of Sapphire material and is transparent to both the terahertz light 5 to be measured and the auxiliary beam 3, as well as to the upconversion fluorescence 6 to be generated. A small amount of metallic cesium (Cs) is filled into the gas cell 1 to generate cesium vapor, and high-purity argon (Ar) is simultaneously filled to 1 atmosphere. At this point, Cs-Ar excimers are generated in the gas cell 1. The permissible wavelength range for the terahertz light 5 is 0.5-3 THz, and the wavelength of the auxiliary beam 3 is... The transition absorbs the blue boundary at approximately 830 nm, which, together with terahertz light, induces energy level transitions in Cs-Ar excimers, such as... Figure 2 As shown, the energy difference between the photons of one auxiliary beam 3 and one terahertz beam 5 triggers A transition, as indicated by the upward arrow. Because... In a repulsive state, it will rapidly dissociate into argon atoms and atoms located at 6... 2 P 3 / 2 Cesium atoms, located at 6 2 P 3 / 2 Cesium atoms transition to the ground state, producing 852 nm fluorescence, which is the upconversion fluorescence 6, as shown by the downward arrow. It reflects the light field distribution of terahertz light 5 illuminating gas cell 1. The upconversion fluorescence 6 is transmitted out of gas cell 1 and captured by a 4-camera, thus realizing the function of terahertz upconversion detection.

[0037] Example 3: A Sensitive Broadband Terahertz Upconversion Detector Based on Rb-He Excimer

[0038] The detector structure is also like this Figure 1As shown. The auxiliary light source 2 emits an auxiliary beam 3 to illuminate the gas cell 1. The gas cell 1 is made of Sapphire material and is transparent to both the terahertz light 5 to be measured and the auxiliary beam 3, as well as to the upconversion fluorescence 6 to be generated. A small amount of metallic rubidium (Rb) is filled into the gas cell 1 to generate rubidium vapor, and high-purity helium (He) is simultaneously added to a pressure of 1 atmosphere. At this point, Rb-He excimers are generated in the gas cell 1. The permissible wavelength range for the terahertz light 5 is 0.5-3 THz, and the wavelength of the auxiliary beam 3 is... The transition absorbs the red boundary at approximately 783 nm, which, together with terahertz light, induces energy level transitions in the Rb-He excimer, such as... Figure 3 As shown, the combined energy of photons from one auxiliary beam 3 and one terahertz beam 5 triggers... The transition, as indicated by the upward arrow, occurs due to A. 2 Π 2 / 3 When in a bound state, it will occur The transition produces broadband fluorescence located between 780nm and 795nm. This fluorescence is the upconversion fluorescence 6, as shown by the downward arrow. It reflects the light field distribution of the terahertz light 5 illuminating the gas cell 1. The upconversion fluorescence 6 is transmitted out of the gas cell 1 and captured by the 4-camera, thus realizing the function of terahertz upconversion detection.

[0039] Example 4: Another sensitive broadband terahertz upconversion detector based on Rb-He excimer

[0040] The detector structure is also like this Figure 1 As shown. The auxiliary light source 2 emits an auxiliary beam 3 to illuminate the gas cell 1. The gas cell 1 is made of Sapphire material and is transparent to both the terahertz light 5 to be measured and the auxiliary beam 3, as well as to the upconversion fluorescence 6 to be generated. A small amount of metallic rubidium (Rb) is filled into the gas cell 1 to generate rubidium vapor, and high-purity helium (He) is simultaneously added to a pressure of 1 atmosphere. At this point, Rb-He excimers are generated in the gas cell 1. The permissible wavelength range for the terahertz light 5 is 0.5-3 THz, and the wavelength of the auxiliary beam 3 is... The transition absorbs the blue boundary at approximately 776 nm, which, together with terahertz light, induces energy level transitions in the Rb-He excimer, such as... Figure 3 As shown, the energy difference between the photons of one auxiliary beam 3 and one terahertz beam 5 triggers The transition, as indicated by the upward arrow, occurs due to A. 2 Π 2 / 3 When in a bound state, it will occur The transition produces broadband fluorescence located between 780nm and 795nm. This fluorescence is the upconversion fluorescence 6, as shown by the downward arrow. It reflects the light field distribution of the terahertz light 5 illuminating the gas cell 1. The upconversion fluorescence 6 is transmitted out of the gas cell 1 and captured by the 4-camera, thus realizing the function of terahertz upconversion detection.

[0041] Example 5: Sensitive Broadband Terahertz Upconversion Detector Based on Cs-He Excimer

[0042] Detector structure as follows Figure 1 As shown. The auxiliary light source 2 emits an auxiliary beam 3 to illuminate the gas cell 1. The gas cell 1 is made of Sapphire material and is transparent to both the terahertz light 5 to be measured and the auxiliary beam 3, as well as to the upconversion fluorescence 6 to be generated. A small amount of metallic cesium (Cs) is filled into the gas cell 1 to generate cesium vapor, and high-purity helium (He) is simultaneously added to a pressure of 1 atmosphere. At this point, Cs-He excimers are generated in the gas cell 1. The permissible wavelength range for the terahertz light 5 is 0.5-3 THz, and the wavelength of the auxiliary beam 3 is... The transition absorbs the red boundary at approximately 454 nm, which, together with terahertz light, induces energy level transitions in the Cs-He excimer. See the energy level diagram for reference. Figure 2 The situation will include View as That's it. The combined energy of a photon from one auxiliary beam (beam 3) and a photon from one terahertz beam (beam 5) triggers... A transition, as indicated by the upward arrow. Because... In a repulsive state, it will rapidly dissociate into helium atoms and atoms located at 7. 2 P 3 / 2 Cesium atoms, located at 7 2 P 3 / 2 Cesium atoms transition to the ground state, producing 455 nm fluorescence, which is the upconversion fluorescence 6, as shown by the downward arrow. It reflects the light field distribution of terahertz light 5 illuminating gas cell 1. The upconversion fluorescence 6 is transmitted out of gas cell 1 and captured by a 4-camera, thus realizing the function of terahertz upconversion detection.

[0043] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A broadband terahertz upconversion detector based on alkali metal inert gas excimers, characterized in that, include: A gas pool for holding alkali metal vapor and inert gas, wherein the alkali metal vapor and inert gas naturally form excimers within the gas pool, and terahertz light can be transmitted from the outside of the gas pool to the inside. An auxiliary light source is used to output an auxiliary beam. The auxiliary beam emitted by the auxiliary light source can be transmitted from the outside of the gas cell to the inside. The auxiliary beam and the terahertz light together induce the excimer to transition from the ground state to the excited state in the gas cell, thereby generating upconversion fluorescence. The upconversion fluorescence can be transmitted from the inside of the gas cell to the outside. A camera used to capture the upconversion fluorescence.

2. The broadband terahertz upconversion detector based on alkali metal inert gas excimers according to claim 1, characterized in that, The terahertz light frequency is in the range of 0.5THz to 10THz.

3. A broadband terahertz upconversion detector based on an alkali metal inert gas excimer according to claim 2, characterized in that, The gas cell is made of Sapphire, the terahertz light frequency is in the range of 0.5-3 THz, the alkali metal vapor is cesium vapor, the inert gas is argon, the auxiliary beam wavelength is 841 nm, and the upconversion fluorescence wavelength is 852 nm.

4. A broadband terahertz upconversion detector based on an alkali metal inert gas excimer according to claim 2, characterized in that, The gas cell is made of Sapphire, the terahertz light frequency is in the range of 0.5-3 THz, the alkali metal vapor is cesium vapor, the inert gas is argon, the auxiliary beam wavelength is 830 nm, and the upconversion fluorescence wavelength is 852 nm.

5. A broadband terahertz upconversion detector based on an alkali metal inert gas excimer according to claim 2, characterized in that, The gas cell is made of Sapphire, the terahertz light frequency is in the range of 0.5-3 THz, the alkali metal vapor is rubidium vapor, the inert gas is helium, the auxiliary beam wavelength is 783 nm, and the upconversion fluorescence wavelength is 780-795 nm.

6. A broadband terahertz upconversion detector based on an alkali metal inert gas excimer according to claim 2, characterized in that, The gas cell is made of Sapphire, the terahertz light frequency is in the range of 0.5-3 THz, the alkali metal vapor is rubidium vapor, the inert gas is helium, the auxiliary beam wavelength is 776 nm, and the upconversion fluorescence wavelength is 780-795 nm.

7. A broadband terahertz upconversion detector based on an alkali metal inert gas excimer according to claim 2, characterized in that, The gas cell is made of Sapphire, the terahertz light frequency is in the range of 0.5-3 THz, the alkali metal vapor is cesium vapor, the inert gas is helium, the auxiliary beam wavelength is 454 nm, and the upconversion fluorescence wavelength is 455 nm.

8. A broadband terahertz upconversion detector based on an alkali metal inert gas excimer according to claim 1, characterized in that, The alkali metal vapor is one or more of lithium vapor, sodium vapor, potassium vapor, rubidium vapor, and cesium vapor.

9. A broadband terahertz upconversion detector based on an alkali metal inert gas excimer according to claim 1, characterized in that, The inert gas is one or more of helium, neon, argon, krypton, and xenon.

10. A broadband terahertz upconversion detector based on an alkali metal inert gas excimer according to claim 1, characterized in that, The auxiliary light source emits an auxiliary beam with one or more discrete wavelengths, of which at least one active wavelength can co-induce excimer energy level transitions with the terahertz light to be detected.

Images