CN206540823U - A kind of Optical devices for being used to differentiate organic components and content - Google Patents

Abstract

An optical device for identifying the composition and content of organic matter belongs to the technical field of detection devices. The utility model adopts a high-precision, large-aperture and low-frequency signal acquisition capable parabolic reflector to effectively collect spectra; utilizes a chopper and a phase locker to control signal noise, greatly suppresses useless noise, and improves the detection signal-to-noise ratio. The detection sensitivity is improved, and the effective detection of weak signals is realized; the optical filter is used to selectively modulate the intensity of the optical signal, which improves the contrast of the signal and realizes the effective analysis of the signal contrast; the absorption in the collected terahertz spectrum is used to The information such as peak position and absorption coefficient is compared with the standard sample to extract the composition and content of the organic sample.

Description

An optical device for identifying the composition and content of organic matter

technical field

The utility model belongs to the technical field of detection devices, in particular to an optical device for identifying organic components and contents.

Background technique

Terahertz light is an electromagnetic wave with a radiation frequency range of 0.1-10THz and a wavelength range of 3mm-30um between microwave and infrared. In the field of electronics, electromagnetic waves in this band are called millimeter waves and submillimeter waves, while in the field of optics, they are called far-infrared rays. The terahertz spectrum emitted through matter contains very rich physical and chemical information, and the study of the spectrum of matter in this band is of great significance for the exploration of matter structure. Compared with traditional light sources, terahertz laser has many unique properties, such as transient, low energy, broadband, coherence, etc., as well as strong penetration of many polar substances and strong absorption of polar molecules Therefore, it has very important application prospects in the fields of basic research, medicine, industry, military and biology. Terahertz spectroscopy is a new and efficient coherent detection technology. Since the transitions between vibrational energy levels and rotational energy levels of many polar macromolecules are just in the terahertz spectral range, there are even a large number of polar molecules in the terahertz frequency band. Therefore, the terahertz spectrum of organic biomolecules can reflect the intrinsic characteristics of low-frequency vibrational modes caused by intramolecular or intermolecular collective vibrations and lattice vibrations. In addition, the collective vibrational modes observed in the absorption spectrum are determined by the configuration and conformation of the entire molecule, reflecting the interaction between the molecule and the environment, so terahertz spectroscopy can also provide direct features for the configuration and conformation of molecules Spectrum. In conclusion, terahertz laser has low photon energy and will not produce harmful photoionization during sample detection. Identification of isomers, etc.

Contents of the invention

The utility model mainly solves the technical problems existing in the above-mentioned prior art, and provides an optical device for identifying the composition and content of organic matter. The interaction of terahertz laser can produce resonance reaction, so as to quickly and sensitively identify the composition and content of organic samples.

The above-mentioned technical problems of the utility model are mainly solved by the following technical solutions: an optical device for identifying the composition and content of organic matter, including a laser, a beam splitter, a parabolic mirror, a terahertz induction crystal and a phase locker , the laser emits laser light, and the beam splitter splits the laser beam into a detection laser and an excitation laser, and the detection laser and the excitation laser have their own branches, converge the beams through a parabolic mirror, and converge on the terahertz sensing crystal synchronously, The rear end of the terahertz sensing crystal is provided with a light splitter, and the phase locker is provided with a photoelectric probe, and the phase locker and the photoelectric probe are connected by a data line of the photoelectric probe, and the photoelectric probe is arranged behind the light splitter. The end is used to detect the optical signal transmitted by the optical splitter. The detection laser branch includes a total reflection mirror, a time delay device and a focusing mirror. The total reflection mirror, time delay device and focusing mirror are placed in sequence, and the excitation The laser branch includes a chopper, an optical filter, a focusing mirror and a terahertz conversion crystal, the chopper, an optical filter, a focusing mirror and a terahertz conversion crystal are placed in sequence, and the chopper is controlled by a chopper The line is connected to the phase locker, the number of the parabolic reflectors is two, and the arrangement of the parabolic reflectors is in the shape of "eight", the center of the left parabolic reflector is provided with a circular hole, and the An organic sample to be measured is arranged between the reflecting mirrors.

Preferably, a wave plate and a focusing mirror are arranged between the terahertz sensing crystal and the beam splitter, the wave plate is located at the rear end of the terahertz sensing crystal, and the focusing mirror is located at the rear end of the wave plate.

Preferably, an optical filter is provided between the optical splitter and the photoelectric probe.

Preferably, the delay device is composed of a total reflection mirror and a linear translation stage, the number of the total reflection mirrors is two, and they are all fixed on the linear translation stage, and the angles of the two total reflection mirrors are right angles to each other.

The method of using the above-mentioned optical device to identify the composition and content of organic matter is as follows:

In step (1), the laser emits laser light, and the beam splitter splits the laser light into detection laser light and excitation laser light;

In step (2), the excitation laser passes through the chopper and the filter respectively, and is converged on the terahertz conversion crystal by the focusing mirror, and interacts with the terahertz conversion crystal to generate a terahertz laser. The terahertz laser is collected by a parabolic mirror, and then combined with The organic samples to be measured interact and transmit, and then converge on the terahertz induction crystal through the parabolic mirror. The chopper and the phase locker cooperate with each other to suppress the strong fundamental frequency signal and lock the weak high frequency signal at the same time, thus Effectively extract high-frequency weak signals carrying sample information, improve the signal-to-noise ratio, and the optical filter can adjust the intensity of the excitation laser light;

In step (3), the detection laser passes through the total reflection mirror, the delayer and the focusing mirror, then passes through the small hole on the left parabolic reflector, and then converges on the terahertz sensing crystal through the parabolic reflector, wherein the delayer The delay control between the detection laser and the excitation laser is realized by translating the total reflection mirror group along the transmission direction of the detection laser, so that the detection laser and the terahertz laser are synchronized and converged on the terahertz sensing crystal together;

In step (4), the optical signal carrying the information of the organic sample to be tested is modulated by the terahertz sensing crystal and the wave chip, and then divided into two comparison beams by the beam splitter. , transmitted to the phase locker through the photoelectric probe data line, and the phase locker analyzes and compares the carrier signal carrying the sample information of the organic matter to be tested, thereby analyzing the sample information it carries.

The principle of using the above-mentioned optical device to identify the composition and content of organic matter is: extract the information such as the position of the absorption peak and the absorption coefficient in the spectral information through the above-mentioned optical device, and verify the composition and content of the organic sample by comparing with the standard information library, that is Different absorption peak positions (i.e. characteristic peaks) correspond to different organic components, so that the organic components can be identified, and the absorption coefficient at the corresponding position of the absorption peak corresponds to different organic content, so that the organic content can be identified. The vibration frequency and rotation frequency of organic matter are in the terahertz spectral range, and the interaction with terahertz laser can produce resonance reaction, so as to quickly and sensitively identify the composition and content of organic matter samples.

The utility model has beneficial effects: the terahertz spectrum is similar to a Gaussian beam, which is a divergent spectrum, and the parabolic reflector with high precision, large aperture and low-frequency signal acquisition ability can effectively collect the spectrum; the chopper and phase-locked The filter controls the signal noise, greatly suppresses the useless noise, improves the detection signal-to-noise ratio, improves the detection sensitivity, and realizes the effective detection of weak signals; uses the optical filter to selectively modulate the optical signal intensity, and improves the contrast of the signal , to realize the effective analysis of signal comparison; use the information such as the absorption peak position and absorption coefficient in the collected terahertz spectrum and compare it with the standard sample to extract the composition and content of the organic sample.

Description of drawings

Fig. 1 is a kind of structural representation of the utility model;

Fig. 2 is a terahertz characteristic spectrum diagram obtained by analyzing a specific implementation example of the present invention.

In the figure: 1. Laser; 2. Beam splitter; 3. Parabolic mirror; 4. Terahertz sensing crystal; 5. Phase locker; 6. Laser; 7. Detection laser; 8. Exciting laser; 9. Beam splitter ;10, photoelectric probe; 11, photoelectric probe data line; 12, total reflection mirror; 13, time delay device; 14, focusing mirror; 15, chopper; 16, optical filter; 17, terahertz conversion crystal; , organic sample to be tested; 19, wave chip; 20, linear translation stage; 21, chopper control line; 22, computer; 23, delayer control line; 24, phase locker control line; 25, terahertz laser .

detailed description

The technical solutions of the present utility model will be further specifically described below through the embodiments and in conjunction with the accompanying drawings.

Embodiment: an optical device for identifying the composition and content of organic matter, as shown in Figure 1, includes a laser, a beam splitter, a parabolic reflector, a terahertz induction crystal, a phase locker and a computer, and the laser emits laser light, The beam splitter splits the laser beam into a detection laser and an excitation laser. The detection laser and the excitation laser have their own branches, and the beams are converged by a parabolic mirror and converged synchronously on the terahertz sensing crystal. The rear of the terahertz sensing crystal is An optical splitter is provided at the end of the optical splitter, and a photoelectric probe is provided on the phase locker, and the phase locker and the photoelectric probe are connected by a photoelectric probe data line. The optical signal transmitted over, the phase locker is connected to the computer through the phase locker control line, and the detection laser branch includes a total reflection mirror, a delayer and a focusing mirror, and the total reflection mirror, a delayer and a focusing The mirrors are placed in sequence, the delayer is connected to the computer through the delayer control line, the excitation laser branch includes a chopper, an optical filter, a focusing mirror and a terahertz conversion crystal, and the chopper, optical filter The chopper, the focusing mirror and the terahertz conversion crystal are placed in sequence. The chopper is connected to the phase locker through the chopper control line. The number of the parabolic mirrors is two, and the parabolic mirrors are placed in the shape of "eight". Type, the center of the left parabolic reflector is provided with a small circular hole, and the organic sample to be tested is arranged between the parabolic reflectors.

A wave plate and a focusing mirror are arranged between the terahertz sensing crystal and the beam splitter, the wave plate is located at the rear end of the terahertz sensing crystal, and the focusing mirror is located at the rear end of the wave plate.

An optical filter is arranged between the optical splitter and the photoelectric probe.

The time delay device is composed of a total reflection mirror and a linear translation platform. There are two total reflection mirrors fixed on the linear translation platform. The angles of the two total reflection mirrors are right angles to each other.

Among them, the laser adopts sapphire femtosecond laser, the wavelength of the output laser is 800nm, the output frequency is 50MHz, the output pulse width is 100fs, and the output power is 500mW; the energy splitting ratio of the beam splitter is 2:1; The wave frequency is 3KHz; the optical filter adopts a disc rotary filter, which can adjust the laser energy; the focusing mirror set on the excitation laser branch adopts a focal length of 500nm, and the focusing mirror set on the detection laser branch adopts a focal length of 800nm. The focusing mirror at the back end of the wave chip adopts a focal length of 300nm; the total reflection mirror adopts a dielectric film total reflection mirror of 800nm; the focal length of the parabolic mirror is 200nm, and a small hole with a diameter of 2mm is dug in the middle of one of the parabolic mirrors; the terahertz conversion crystal It is a gallium arsenide crystal, and a voltage needs to be applied to both ends to improve the conversion efficiency of terahertz; the terahertz sensing crystal is zinc telluride crystal; the wave chip adopts 800nm 1/4 wave plate; The photoelectric probe can convert the optical signal into an electrical signal; the organic matter samples to be tested are various edible oils purchased from supermarkets and waste oil collected outdoors; the computer is used to control the scanning speed of the delayer and accept the acquisition from the phase locker data.

The experimental process is as follows: the sapphire femtosecond laser outputs 800nm femtosecond laser, which is split into excitation laser and detection laser by a beam splitter. The reflector collects and radiates on the sample, and then the terahertz spectrum carrying the sample information and the detection laser are copolymerized on the zinc telluride crystal, interact with the zinc telluride crystal and be detected and sensed by the photoelectric probe; the computer controls the delay to adjust the excitation The time delay between the laser and the detection laser can scan the time-domain waveform of the terahertz pulse. The signal detected by the photoelectric probe is extracted by the phase locker and sent to the computer. The computer performs Fourier transform on the time-domain signal, that is Terahertz frequency domain spectrograms can be obtained.

Fig. 2 is the terahertz characteristic spectrum of the empty sample tank, soybean oil, rapeseed oil, corn oil, blended oil, sesame oil and gutter oil obtained by scanning with the above optical device. It can be seen from the figure that there are differences in the absorption peak position and amplitude intensity of different edible oil samples. Different absorption peak positions represent different organic components, and different amplitude intensities represent different contents. Using the above optical device can effectively identify The composition and content of edible oil and other information.

Finally, it should be pointed out that the above embodiments are only representative examples of the present utility model. Apparently, the utility model is not limited to the above-mentioned embodiments, and many variations are possible. Any simple modifications, equivalent changes and modifications made to the above embodiments according to the technical essence of the present invention shall be deemed to belong to the protection scope of the present invention.

Claims (4)

1. It is used to differentiating the Optical devices of organic components and content 1. a kind of, including laser, beam splitter, parabolic mirror, too Hertz sensing crystal and phase locking unit, it is characterised in that the laser launches laser, beam splitter is by laser beam splitter into exploring laser light And excitation laser, the respective branch road of exploring laser light and the excitation laser approach, pass through parabolic mirror convergence and close beam, synchronous convergence In on Terahertz sensing crystal, the rear end of the Terahertz sensing crystal is provided with optical splitter, and the phase locking unit is visited provided with photoelectricity Head, is connected between phase locking unit and photoelectric probe by photoelectric probe data wire, and the photoelectric probe is arranged on the rear end of optical splitter, Receive the optical signal that optical splitter is transmitted for detecting, the exploring laser light branch road includes completely reflecting mirror, delayer and focusing Mirror, the completely reflecting mirror, delayer and focus lamp are sequentially placed, and the excitation laser branch road includes chopper, filter, focusing Mirror and Terahertz conversion crystal, the chopper, filter, focus lamp and Terahertz conversion crystal are sequentially placed, the copped wave Device is connected by chopper control line with phase locking unit, and the parabolic mirror quantity is two, and putting for parabolic mirror is in " eight " font, the center of the left side parabolic mirror is provided between circular aperture, the parabolic mirror to be had provided with to be measured Machine thing sample.
2. 2. a kind of according to claim 1 be used to differentiate the Optical devices of organic components and content, it is characterised in that described Terahertz, which senses, is provided with quarter wave plate 14 and focus lamp between crystal and optical splitter, quarter wave plate 14 is located at after Terahertz sensing crystal End, focus lamp is located at the rear end of quarter wave plate 14.
3. 3. a kind of according to claim 1 be used to differentiate the Optical devices of organic components and content, it is characterised in that described Filter is provided between optical splitter and photoelectric probe.
4. 4. a kind of according to claim 1 be used to differentiate the Optical devices of organic components and content, it is characterised in that described Delayer is made up of completely reflecting mirror and rectilinear translation platform, and the quantity of the completely reflecting mirror is two, is both secured to rectilinear translation platform On, the angles of described two completely reflecting mirrors right angle each other.