CN112556998B - Tunable laser wavelength calibration system and method based on photoacoustic spectroscopy - Google Patents
Tunable laser wavelength calibration system and method based on photoacoustic spectroscopy Download PDFInfo
- Publication number
- CN112556998B CN112556998B CN202011430778.8A CN202011430778A CN112556998B CN 112556998 B CN112556998 B CN 112556998B CN 202011430778 A CN202011430778 A CN 202011430778A CN 112556998 B CN112556998 B CN 112556998B
- Authority
- CN
- China
- Prior art keywords
- resistor
- photoacoustic
- wavelength
- capacitor
- gas
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
- 238000004867 photoacoustic spectroscopy Methods 0.000 title claims abstract description 20
- 238000000034 method Methods 0.000 title claims abstract description 13
- 238000005086 pumping Methods 0.000 claims abstract description 17
- 239000011521 glass Substances 0.000 claims abstract description 4
- 239000003990 capacitor Substances 0.000 claims description 33
- 238000010521 absorption reaction Methods 0.000 claims description 26
- 230000000737 periodic effect Effects 0.000 claims description 12
- WUKWITHWXAAZEY-UHFFFAOYSA-L calcium difluoride Chemical compound [F-].[F-].[Ca+2] WUKWITHWXAAZEY-UHFFFAOYSA-L 0.000 claims description 3
- 229910001634 calcium fluoride Inorganic materials 0.000 claims description 3
- 229910001220 stainless steel Inorganic materials 0.000 claims description 3
- 239000010935 stainless steel Substances 0.000 claims description 3
- 239000000463 material Substances 0.000 claims 1
- 230000001105 regulatory effect Effects 0.000 claims 1
- 238000005516 engineering process Methods 0.000 abstract description 4
- 239000007789 gas Substances 0.000 description 42
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 9
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 8
- 230000003287 optical effect Effects 0.000 description 6
- 238000013461 design Methods 0.000 description 5
- 150000003384 small molecules Chemical class 0.000 description 5
- 229910021529 ammonia Inorganic materials 0.000 description 4
- 230000003321 amplification Effects 0.000 description 3
- 238000010586 diagram Methods 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 238000001914 filtration Methods 0.000 description 3
- 238000003199 nucleic acid amplification method Methods 0.000 description 3
- VGGSQFUCUMXWEO-UHFFFAOYSA-N Ethene Chemical compound C=C VGGSQFUCUMXWEO-UHFFFAOYSA-N 0.000 description 2
- 239000005977 Ethylene Substances 0.000 description 2
- HSFWRNGVRCDJHI-UHFFFAOYSA-N alpha-acetylene Natural products C#C HSFWRNGVRCDJHI-UHFFFAOYSA-N 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 2
- 238000001514 detection method Methods 0.000 description 2
- 125000002534 ethynyl group Chemical group [H]C#C* 0.000 description 2
- 238000001834 photoacoustic spectrum Methods 0.000 description 2
- 238000001228 spectrum Methods 0.000 description 2
- 238000001845 vibrational spectrum Methods 0.000 description 2
- 239000002390 adhesive tape Substances 0.000 description 1
- 238000004891 communication Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 238000002329 infrared spectrum Methods 0.000 description 1
- -1 methyl halide Chemical class 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000007789 sealing Methods 0.000 description 1
- 230000005236 sound signal Effects 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 238000012546 transfer Methods 0.000 description 1
Images
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
- G01M11/00—Testing of optical apparatus; Testing structures by optical methods not otherwise provided for
- G01M11/02—Testing optical properties
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
- G01J3/00—Spectrometry; Spectrophotometry; Monochromators; Measuring colours
- G01J3/28—Investigating the spectrum
- G01J3/42—Absorption spectrometry; Double beam spectrometry; Flicker spectrometry; Reflection spectrometry
Abstract
The invention discloses a tunable laser wavelength calibration system and a method based on a photoacoustic spectroscopy technology, wherein the system comprises the following components: the system comprises a signal generator, a pumping unit, an infrared laser, a small molecular gas pool, an amplifying unit and a computer; the small molecular gas cell comprises a photoacoustic cell which is in a sealed state and is filled with gas, and a radio device is arranged in the inner cavity of the photoacoustic cell; the radio device is connected with the amplifier and the computer in sequence; the computer is connected with the infrared laser, the computer, the signal generator, the pumping unit and the infrared laser are sequentially connected, and laser output by the infrared laser irradiates gas in the photoacoustic cell. The instrument can be realized by only one glass cavity, a miniature microphone, a self-made signal amplifier, an oscilloscope or a computer, and the like. Small, simple and inexpensive, and small, simple and inexpensive.
Description
Technical Field
The invention relates to the technical field of photoacoustic spectroscopy, in particular to a tunable laser wavelength calibration system and method based on the photoacoustic spectroscopy technology.
Background
Infrared light is an electromagnetic wave that is invisible to the naked eye and has a wavelength in the range of 1 millimeter to 750 nanometers. The wavelength-tunable infrared light has wide application in detection, communication, medical treatment, experimental study, military and other fields. The infrared light sources capable of generating wavelength tunable infrared light are mainly: an infrared Optical Parametric Oscillator (OPO), a Quantum Cascade Laser (QCL), a laser Difference Frequency (DFG) infrared light source, and the like. However, the above infrared light sources mainly rely on mechanical control and temperature control to tune the output infrared light wavelength, so that the output infrared light wavelength has a certain error with the actual wavelength. To obtain an accurate infrared wavelength, the infrared wavelength output by the laser needs to be calibrated, and usually, people measure the light wave emitted by the laser through an infrared wavelength measuring instrument and then calibrate, for example, the infrared light of the laser is measured and calibrated by using a waveScan infrared wavelength measuring instrument manufactured by the germany APE company. However, such instruments are not only bulky, but also very expensive. And high quality optical elements such as high reflection mirrors, lenses, gratings and the like, as well as photodetectors, control computers and the like, are required to be used, the volume and weight of the instrument are large, and the price is relatively high.
There is therefore a great need in the industry to develop a method or system for correcting the wavelength of an infrared laser that is easy to operate and inexpensive.
Disclosure of Invention
The invention aims to overcome the defects in the prior art, and provides a tunable laser wavelength calibration system and a tunable laser wavelength calibration method based on a photoacoustic spectroscopy technology, which are convenient to operate and low in cost.
The aim of the invention is achieved by the following technical scheme:
a tunable laser wavelength calibration system based on photoacoustic spectroscopy, comprising: the system comprises a signal generator, a pumping unit, an infrared laser, a small molecular gas pool, an amplifying unit and a computer; the small molecular gas cell comprises a photoacoustic cell which is in a sealed state and is filled with gas, and a radio device is arranged in the inner cavity of the photoacoustic cell; the radio device is connected with the amplifier and the computer in sequence; the computer is connected with the infrared laser, the computer, the signal generator, the pumping unit and the infrared laser are sequentially connected, and laser output by the infrared laser irradiates gas in the photoacoustic cell.
Preferably, the sound pickup means is a microphone or a piezoceramic microphone.
Preferably, the amplifying unit includes: the first-stage amplifier U1, the second-stage amplifier U2, the resistor R1, the resistor R2, the resistor R3, the resistor R4 and the resistor R5, the capacitor C1, the capacitor C2 and the capacitor C3; the resistor R5 is a slide rheostat; the two input ends of the first-stage amplifier U1 are connected with the radio device, the forward input end of the first-stage amplifier U1 is connected with the output end through a resistor R1, the output of the first-stage amplifier U1 is connected with one end of a resistor R2 and one end of a capacitor C1, the other end of the resistor R3 is connected with the reverse input end of the second-stage amplifier U2 and one end of the capacitor C2, the other end of the capacitor C2 is connected to the ground, the other end of the capacitor C1 is connected with the same-direction input end of the second-stage amplifier U2, one end of a capacitor C3 and one fixed end of a resistor R5, the other fixed end of the resistor R5, the sliding end of the resistor R5 and the other end of the capacitor C3 are connected with the output end of the second-stage amplifier U2, and the output end of the second-stage amplifier U2 is also connected with a computer; the resistor R2, the resistor R3, the capacitor C1 and the capacitor C2 and the connection thereof form an RC pi type filter circuit.
Preferably, the first stage amplifier U1 is of the type AD620 and the second stage amplifier U2 is of the type TLV2711CDBVR.
Preferably, the small molecule gas tank further comprises an upper cavity, a lower cavity and a cylinder; go up the cavity, down the cavity and press from both sides the pressfitting connection through stainless steel ball mill mouth, the cylinder is connected to the lower part of lower cavity, and the sound-receiving device sets up at the cylinder, and the photoacoustic cell is connected to the lower part of cylinder, cylinder and photoacoustic cell intercommunication, and the one side window of photoacoustic cell side income light is provided with the calcium fluoride lens, and the air flue connection mechanical pump interface of photoacoustic cell lower part has the overhead valve that is used for separating loading and unloading gaseous part and photoacoustic cell.
Preferably, a tunable laser wavelength calibration system based on photoacoustic spectroscopy further comprises: a power supply circuit; the power supply circuit is connected with the amplifying unit and the radio device.
Preferably, the power supply circuit comprises a direct current power supply, and the direct current power supply is a direct current stabilized voltage power supply or a dry battery.
A tunable laser wavelength calibration method based on photoacoustic spectroscopy, comprising: the pumping unit outputs pumping light to the infrared laser, the infrared laser outputs continuous infrared laser with the wavelength under the action of the pumping light, the infrared laser irradiates gas in the photoacoustic cell, if the wavelength of the incident light is consistent with the absorption wavelength of gas molecules at the moment, the gas molecules absorb the laser, periodic pressure fluctuation is generated, the radio device detects the periodic pressure fluctuation of the gas molecules, the periodic pressure fluctuation is amplified by the amplifying unit to obtain a photoacoustic signal, the vibration absorption peak position of the photoacoustic signal is compared with the vibration absorption peak position fixed by known molecules, and if the vibration absorption peak position of the photoacoustic signal is inconsistent with the vibration absorption peak position fixed by the known molecules, the output wavelength of the infrared laser is controlled by a computer, so that the calibration of the output wavelength of the infrared laser is realized.
Preferably, when the wavelength generated by the laser is not the wavelength position corresponding to the infrared characteristic peak of the gas, the infrared energy absorption is very small, the air pressure disturbance is not generated, and the periodical pressure fluctuation of the gas molecules can not be detected by the radio device.
Compared with the prior art, the invention has the following advantages:
according to the invention, infrared light emitted by a tunable infrared laser (tunable IR laser) irradiates into a photoacoustic cell (Gas cell) filled with Gas small molecules, the incident wavelength is continuously changed, when the incident wavelength coincides with the absorption wavelength of the Gas small molecules, pulse incident light is absorbed, and the energy of the Gas small molecules is increased, so that the medium generates periodic pressure fluctuation. At this time, the radio receiver receives the vibration signal of the gas molecule, the converter converts the sound signal of the tiny vibration into the voltage signal, then transmit the tiny voltage signal to the amplifier, the amplifier amplifies the signal and then transmits the signal out, because the light generated by the optical parametric oscillator irradiates with a long wave band, thus the photoacoustic spectrogram of the gas is obtained. Finally, the light of the wave band emitted by the infrared spectrometer is calibrated according to the known absorption peak position of the gas molecules. Therefore, the instrument only needs a glass cavity, a miniature microphone, a self-made signal amplifier, an oscilloscope or a computer and the like. Small, simple and inexpensive.
Drawings
The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the invention. In the drawings:
fig. 1 is a schematic structural diagram of a tunable laser wavelength calibration system based on photoacoustic spectroscopy according to the present invention.
FIG. 2 is a schematic diagram of a small molecular gas cell according to the present invention.
Fig. 3 is a circuit diagram of an amplifying unit of the present invention.
FIG. 4 (a) is a graph showing the absorption peak of methane vibration.
FIG. 4 (b) is a graph showing the ammonia slip absorption peak.
Detailed Description
The invention is further described below with reference to the drawings and examples.
The photoacoustic spectroscopy technology is utilized, and the wavelength emitted by the infrared wavelength tunable laser is measured and calibrated through the response of a specific gaseous micromolecule (such as methane, ammonia and other molecules) to infrared light with a specific wavelength. The specific scheme is as follows:
referring to fig. 1-2, a tunable laser wavelength calibration system based on photoacoustic spectroscopy, comprising: the system comprises a signal generator 7, a pumping unit 1, an infrared laser 2, a small molecular gas tank 3, an amplifying unit 5 and a computer 6; the small molecular gas cell 3 comprises a photoacoustic cell 34, the photoacoustic cell 34 is in a sealed state, the cavity is filled with gas, and a radio device 4 is arranged in the cavity of the photoacoustic cell; the radio device 4 is connected with the amplifier 5 and the computer 6 in sequence; the computer 6 is connected with the infrared laser 2, the computer 6, the signal generator 7, the pumping unit 1 and the infrared laser 2 are sequentially connected, and laser output by the infrared laser 2 irradiates gas in the photoacoustic cell.
In this embodiment, the sound pickup device 4 is a microphone.
Referring to fig. 2, the main body of the small molecular gas cell is made of common glass, in order to place the sound receiving device 4, the upper cavity 31 and the lower cavity 32 are connected by stainless steel ball grinding clamps in a pressing manner, the lower part of the lower cavity 32 is connected with a cylinder, the sound receiving device is arranged on the cylinder 33, the lower part of the cylinder 33 is connected with a photoacoustic cell, the cylinder 33 is communicated with the photoacoustic cell 34, and the photoacoustic cell 34 belongs to a cavity type photoacoustic cell 34 and has three resonance modes, namely radial, tangential and longitudinal. In terms of acoustic wave propagation loss, adhesive tape loss occurs at both the side and end faces in the radial and tangential directions, whereas acoustic waves in the longitudinal resonance mode and the resonant cavity of the photoacoustic cell 34 are perpendicular to the end faces and are parallel to the end faces, so that loss occurs only at the end faces, so that loss is minimized. The side of the photoacoustic cell 34 that is light-entering is provided with a calcium fluoride lens as a window mirror so that infrared light can be emitted into the gas cell for detection and calibration. The lower gas passage of the photoacoustic cell 34 is connected to a mechanical pump interface 36 with a top valve 35 for separating the loading and unloading gas portion from the photoacoustic cell 34. The top valve 35 separates the lower gas handling portion from the photoacoustic cell 34, allowing the upper photoacoustic cell 34 to achieve the desired sealing conditions. The bottom interface 36 is externally connected with a mechanical pump and matched with the top valve 35 to pump out gas in the cavity, so that higher air tightness of the device and gas loading and unloading are realized. The curved design of the top valve 35 to the bottom interface minimizes the volume and use conditions of the device. The use of the top valve 35 helps to handle the gas and allow the photoacoustic cell 34 to achieve the desired containment conditions.
In the present embodiment, referring to fig. 3, the amplifying unit 5 includes: the first-stage amplifier U1, the second-stage amplifier U2, the resistor R1, the resistor R2, the resistor R3, the resistor R4 and the resistor R5, the capacitor C1, the capacitor C2 and the capacitor C3; the resistor R5 is a slide rheostat; the two input ends of the first-stage amplifier U1 are connected with the radio receiving device 4, the forward input end of the first-stage amplifier U1 is connected with the output end through a resistor R1, the output of the first-stage amplifier U1 is connected with one end of a resistor R2 and one end of a capacitor C1, the other end of the resistor R3 is connected with the reverse input end of the second-stage amplifier U2 and one end of the capacitor C2, the other end of the capacitor C2 is connected to the ground, the other end of the capacitor C1 is connected with the same-direction input end of the second-stage amplifier U2, one end of a capacitor C3 and one fixed end of a resistor R5, the other fixed end of the resistor R5, the sliding end of the resistor R5 and the other end of the capacitor C3 are connected with the output end of the second-stage amplifier U2, and the output end of the second-stage amplifier U2 is also connected with the computer 6;
the resistor R2, the resistor R3, the capacitor C1 and the capacitor C2 are connected to form an RC pi type filter circuit; the model of the first stage amplifier U1 is AD620, and the model of the second stage amplifier U2 is TLV2711CDBVR. AD620 is a low-cost, high-precision amplifier component, and only an external resistor is needed to set the adjustable gain, so that the AD620 is an ideal choice of precision data acquisition systems such as micro-voltage and sensor interfaces. In order to maximize the gain effect of the amplifier, the amplifying circuit of the device adopts a two-stage amplifying design. The AD620 is adopted in the first stage, the VACC operational amplifier is adopted in the second stage, and the gain of the amplifier can reach 400-1000 times due to the design of two-stage amplification.
In order to improve various working performances of the amplifying circuit, the amplifying circuit has two innovation points, namely, the RC pi type filtering circuit is innovatively added between two stages of amplification, so that the risk that tiny voltage signals and noise are filtered together before the filtering circuit is placed in a first stage is eliminated, and the situation that the filtering circuit cannot filter the noise efficiently after a second stage is avoided. The design furthest improves the signal to noise ratio on the basis of furthest retaining the original signal. Second, the ultra-high gain allows for efficient and sufficient amplification of the minute voltage signal.
The second innovation point is that the AD620 part of the amplifying circuit needs positive power supply and negative power supply to stably work, the negative power supply needed by the AD620 is converted directly by the positive power supply by the ICL7660 negative power supply converter, the use of multiple (negative) power supplies is reduced, and a better effect is obtained in experiments.
The data acquisition system at the computer 6 end designs two different acquisition systems according to the working conditions of users: the first data acquisition mode adopts an analog circuit to acquire data, namely, an oscilloscope is used for acquiring signals, and the oscilloscope is connected with a computer 6 through a network cable of a TCP protocol to acquire data. Finally, the photoacoustic spectrogram of the small gas is obtained. The acquisition method is suitable for most laboratories in the spectrum field, and has great practical applicability. The second acquisition system directly skips the part of the signal input from the amplifying circuit to the oscilloscope. The AD converter is utilized to directly convert the amplified voltage signal into a binary digital signal by adopting an analog-to-digital conversion method, the binary digital signal is input into the computer 6, and the photo-acoustic spectrum of the small gas molecules is finally acquired by the computer 6.
In this embodiment, the tunable laser wavelength calibration system based on the photoacoustic spectroscopy technique further includes: a power supply circuit; the power supply circuit is connected with the amplifying unit 5 and the radio receiving device 4. The power supply circuit comprises a direct current power supply, and the direct current power supply is a direct current stabilized voltage power supply. The common DC power supply has super-strong practical significance in reducing the requirement of the amplifier on the working voltage. In order to make the photoacoustic signal not affected by the voltage fluctuation of the power supply circuit and make the amplifier circuit in a stable amplifying working state, the output voltage of the direct current power supply needs to be stabilized at 5v.
The tunable laser wavelength calibration method based on the photoacoustic spectroscopy is applicable to the tunable laser wavelength calibration system based on the photoacoustic spectroscopy, and comprises the following steps: the pumping unit 1 outputs pumping light to the infrared laser 2, the infrared laser 2 outputs continuous-wavelength infrared laser under the action of the pumping light, the infrared laser irradiates the gas in the photoacoustic cell 34, and if the wavelength of the infrared laser is not consistent with the absorption wavelength of gas molecules, the infrared laser is not absorbed; if the wavelength of the laser light coincides with the absorption wavelength of the gas molecules, the infrared laser light is absorbed by the molecules and is de-excited in a manner of releasing heat energy, and the released heat energy causes the gas and the surrounding medium to generate periodic pressure fluctuation according to the modulation frequency of the light, so that the gas and the surrounding medium generate periodic pressure fluctuation, the acoustic receiving device 4 detects the periodic pressure fluctuation, and the periodic pressure fluctuation is amplified by the amplifying unit 5 to obtain an optical acoustic signal, so that the conversion (i.e., the optical acoustic effect) of the optical signal and the acoustic signal is realized. Comparing the vibration absorption peak position of the photoacoustic signal with the vibration absorption peak position fixed by the known molecules, and controlling the output wavelength of the infrared laser 2 through the computer 6 if the vibration absorption peak of the photoacoustic signal is inconsistent with the vibration absorption peak fixed by the known molecules, so as to realize the calibration of the output wavelength of the infrared laser 2. The obtained photoacoustic signal is actually the vibration spectrum of the gas in the photoacoustic cavity, and by comparing the photoacoustic signal with the standard spectrograms of the molecules, the difference of whether the wavelength of infrared light emitted by the infrared tunable laser is accurate or not, which can be obtained by photoacoustic spectrum absorption, so that the scanned wavelength of the light can be calibrated.
Infrared light of different wavelengths due to different molecules has the characteristic of selective absorption. The gas small molecules such as methane, ammonia and the like have very fine vibration-transfer absorption peaks in an infrared spectrum. In theory, the vibration response peak of each sound molecule is a linear spectrum, and the resolution ratio is extremely high. When known simple molecules of gas (e.g., methane, ammonia, ethylene, acetylene, etc.) are placed in photoacoustic cell 34, the infrared wavelength tunable laser wavelength can be calibrated by comparing with the vibration absorption peaks (e.g., fig. 4 (a) and 4 (b)) where the known molecules are fixed. For exampleMethane and ammonia gas are put in. Its vibration spectrum covers 700-1800cm -1 And 2800-3600cm -1 . The above range of infrared tunable lasers can thus be corrected by this device. If the mid-infrared light of other wave bands needs to be corrected, other gases can be put in, for example: acetylene, ethylene, methyl halide, and the like.
The above embodiments are preferred examples of the present invention, and the present invention is not limited thereto, and any other modifications or equivalent substitutions made without departing from the technical aspects of the present invention are included in the scope of the present invention.
Claims (6)
1. A tunable laser wavelength calibration system based on photoacoustic spectroscopy, comprising: the system comprises a signal generator, a pumping unit, an infrared laser, a small molecular gas pool, an amplifying unit and a computer; the small molecular gas cell comprises a photoacoustic cell which is in a sealed state and is filled with gas, and a radio device is arranged in the inner cavity of the photoacoustic cell; the radio device is connected with the amplifier and the computer in sequence; the computer is connected with the infrared laser, the computer, the signal generator, the pumping unit and the infrared laser are sequentially connected, and laser output by the infrared laser irradiates gas in the photoacoustic cell;
the amplifying unit includes: the first-stage amplifier U1, the second-stage amplifier U2, the resistor R1, the resistor R2, the resistor R3, the resistor R4 and the resistor R5, the capacitor C1, the capacitor C2 and the capacitor C3; the resistor R5 is a slide rheostat;
the two input ends of the first-stage amplifier U1 are connected with the radio device, the forward input end of the first-stage amplifier U1 is connected with the output end through a resistor R1, the output of the first-stage amplifier U1 is connected with one end of a resistor R2 and one end of a capacitor C1, the other end of the resistor R3 is connected with the reverse input end of the second-stage amplifier U2 and one end of the capacitor C2, the other end of the capacitor C2 is connected to the ground, the other end of the capacitor C1 is connected with the same-direction input end of the second-stage amplifier U2, one end of a capacitor C3 and one fixed end of a resistor R5, the other fixed end of the resistor R5, the sliding end of the resistor R5 and the other end of the capacitor C3 are connected with the output end of the second-stage amplifier U2, and the output end of the second-stage amplifier U2 is also connected with a computer;
the resistor R2, the resistor R3, the capacitor C1 and the capacitor C2 are connected to form an RC pi type filter circuit; the model of the first-stage amplifier U1 is AD620, and the model of the second-stage amplifier U2 is TLV2711CDBVR;
the negative power required by the AD620 is directly converted by a positive power supply by using an ICL7660 negative power converter;
the main body material of the small molecular gas tank is composed of common glass, and the small molecular gas tank also comprises an upper cavity, a lower cavity and a cylinder; go up the cavity, down the cavity presss from both sides the pressfitting through stainless steel ball mill mouth and is connected, and the cylinder is connected to the lower part of lower cavity, and the sound-receiving device sets up at the cylinder, and the photoacoustic cell is connected to the lower part of cylinder, and cylinder and photoacoustic cell intercommunication, photoacoustic cell side go into the one side of light and are provided with the calcium fluoride lens, and the air flue connection mechanical pump interface of photoacoustic cell lower part has the overhead valve that is used for separating loading and unloading gaseous part and photoacoustic cell.
2. The tunable laser wavelength calibration system according to claim 1, wherein the acoustic receiver is a microphone or a piezoceramic microphone.
3. The tunable laser wavelength calibration system based on photoacoustic spectroscopy of claim 1, further comprising: a power supply circuit; the power supply circuit is connected with the amplifying unit and the radio device.
4. A tunable laser wavelength calibration system according to claim 3, wherein the power supply circuit comprises a dc power supply, which is a dc regulated power supply or a dry cell.
5. A tunable laser wavelength calibration method based on photoacoustic spectroscopy, applied to the tunable laser wavelength calibration system based on photoacoustic spectroscopy as claimed in any one of claims 1 to 4, comprising: the pumping unit outputs pumping light to the infrared laser, the infrared laser outputs continuous infrared laser with the wavelength under the action of the pumping light, the infrared laser irradiates gas in the photoacoustic cell, if the wavelength of the incident light is consistent with the absorption wavelength of gas molecules at the moment, the gas molecules absorb the laser, periodic pressure fluctuation is generated, the radio device detects the periodic pressure fluctuation of the gas molecules, the periodic pressure fluctuation is amplified by the amplifying unit to obtain a photoacoustic signal, the vibration absorption peak position of the photoacoustic signal is compared with the vibration absorption peak position fixed by known molecules, and if the vibration absorption peak position of the photoacoustic signal is inconsistent with the vibration absorption peak position fixed by the known molecules, the output wavelength of the infrared laser is controlled by a computer, so that the calibration of the output wavelength of the infrared laser is realized.
6. The method for calibrating wavelength of tunable laser based on photoacoustic spectroscopy according to claim 5, wherein when the wavelength generated by the laser is not the wavelength position corresponding to the characteristic peak of infrared gas, the infrared energy absorption is small, no air pressure disturbance is generated, and the periodic pressure fluctuation of the gas molecules is not detected by the sound receiving device.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011430778.8A CN112556998B (en) | 2020-12-09 | 2020-12-09 | Tunable laser wavelength calibration system and method based on photoacoustic spectroscopy |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011430778.8A CN112556998B (en) | 2020-12-09 | 2020-12-09 | Tunable laser wavelength calibration system and method based on photoacoustic spectroscopy |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN112556998A CN112556998A (en) | 2021-03-26 |
| CN112556998B true CN112556998B (en) | 2023-06-23 |
Family
ID=75059931
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202011430778.8A Active CN112556998B (en) | 2020-12-09 | 2020-12-09 | Tunable laser wavelength calibration system and method based on photoacoustic spectroscopy |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN112556998B (en) |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4051371A (en) * | 1976-04-26 | 1977-09-27 | Massachusetts Institute Of Technology | Opto-acoustic spectroscopy employing amplitude and wavelength modulation |
| CN104849214A (en) * | 2015-04-20 | 2015-08-19 | 北京航天控制仪器研究所 | Enhanced multi-group photoacoustic spectrum gas sensing device based on quartz tuning fork |
| CN105699329A (en) * | 2016-04-08 | 2016-06-22 | 济南大学 | Wavelength scanning spectrum gas detection system and method based on double optical fiber annular cavities |
| CN111157456A (en) * | 2019-12-31 | 2020-05-15 | 西安电子科技大学 | Gas detection system based on open type photoacoustic resonant cavity |
| CN211602897U (en) * | 2019-12-26 | 2020-09-29 | 湖北鑫英泰系统技术股份有限公司 | Photoacoustic cell structure in photoacoustic spectrum oil gas detection device |
| CN213658228U (en) * | 2020-12-09 | 2021-07-09 | 华南师范大学 | Tunable laser wavelength calibration system based on photoacoustic spectroscopy technology |
-
2020
- 2020-12-09 CN CN202011430778.8A patent/CN112556998B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4051371A (en) * | 1976-04-26 | 1977-09-27 | Massachusetts Institute Of Technology | Opto-acoustic spectroscopy employing amplitude and wavelength modulation |
| CN104849214A (en) * | 2015-04-20 | 2015-08-19 | 北京航天控制仪器研究所 | Enhanced multi-group photoacoustic spectrum gas sensing device based on quartz tuning fork |
| CN105699329A (en) * | 2016-04-08 | 2016-06-22 | 济南大学 | Wavelength scanning spectrum gas detection system and method based on double optical fiber annular cavities |
| CN211602897U (en) * | 2019-12-26 | 2020-09-29 | 湖北鑫英泰系统技术股份有限公司 | Photoacoustic cell structure in photoacoustic spectrum oil gas detection device |
| CN111157456A (en) * | 2019-12-31 | 2020-05-15 | 西安电子科技大学 | Gas detection system based on open type photoacoustic resonant cavity |
| CN213658228U (en) * | 2020-12-09 | 2021-07-09 | 华南师范大学 | Tunable laser wavelength calibration system based on photoacoustic spectroscopy technology |
Non-Patent Citations (1)
| Title |
|---|
| 激光光声功率计;明长江;《激光杂志》;19820415;第3卷(第02期);全文 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN112556998A (en) | 2021-03-26 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN213658228U (en) | Tunable laser wavelength calibration system based on photoacoustic spectroscopy technology | |
| JP5039137B2 (en) | Cavity-enhanced photoacoustic trace gas detector with improved feedback loop | |
| US20090249861A1 (en) | Stable photo acoustic trace gas detector with optical power enhancement cavity | |
| CN104535531A (en) | Handheld laser gas concentration monitor and control method thereof | |
| Rousseau et al. | Off-beam QEPAS sensor using an 11-μm DFB-QCL with an optimized acoustic resonator | |
| US9989729B2 (en) | Ultra stable resonant cavity for gas analysis systems | |
| CN111157456B (en) | Gas detection system based on open type photoacoustic resonant cavity | |
| CN106654844A (en) | Device and method for isotope detection on-line frequency locking based on room temperature QCL laser | |
| CN104931427A (en) | Opto-acoustic gas detection device based on multiple reflections of optical path | |
| US7064329B2 (en) | Amplifier-enhanced optical analysis system and method | |
| CN112556998B (en) | Tunable laser wavelength calibration system and method based on photoacoustic spectroscopy | |
| CN111579495A (en) | Photoacoustic spectrum oil gas monitoring unit | |
| US20030038237A1 (en) | Amplifier-enhanced optical analysis system and method | |
| CN113075130A (en) | Photoacoustics gas concentration detection device and control method thereof | |
| Pan et al. | Cavity-enhanced photoacoustic sensor based on a whispering-gallery-mode diode laser | |
| Barbieri et al. | Gas detection with quantum cascade lasers: An adapted photoacoustic sensor based on Helmholtz resonance | |
| Fan et al. | Compact optical fiber photoacoustic gas sensor with integrated multi-pass cell | |
| Tittel et al. | Sensitive detection of nitric oxide using a 5.26 μm external cavity quantum cascade laser based QEPAS sensor | |
| CN107024432A (en) | A kind of simple optoacoustic detector for being used to detect highly corrosive gas | |
| CN112858206A (en) | Tunable FPI-based intermediate infrared gas measurement method and device | |
| CN114235699A (en) | Trace gas concentration detection device | |
| CN212808028U (en) | Photoacoustic spectrum oil gas monitoring unit | |
| CN115014631B (en) | High vacuum measurement system suitable for easy ionized gas | |
| CN206638574U (en) | A kind of simple optoacoustic detector for being used to detect highly corrosive gas | |
| Röper et al. | Intracavity photoacoustic resonance spectroscopy of C 2 H 4 |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |