[heavy] Jianzhi instrument MOEMS array spot detection technology

[ China Instrument Network Instrument Development ] In recent years, Raman spectroscopy rapid inspection technology in food safety, biomedicine, molecular structure research, chemical processes, biochemistry, archaeological and cultural relics identification, public security and legal sample analysis, anti-terrorism technology and other industries Widely used, Raman spectroscopy, known as "molecular fingerprinting", is highly praised in the field of optical inspection because of its excellent characteristics of losslessness, convenience, speed and stability.

However, it is known that the Raman spectroscopy method has been used. Since the focus measurement method is adopted, care must be taken when detecting some targets. It can be known from the object-image conjugate relationship that only all optical signals emitted by the spectrometer receiving the slit image point can be received by the spectrometer. Therefore, the Raman signal has the highest collection efficiency when the focus of the excitation laser is just at this position. In order to obtain higher resolution, the slit of the dispersive spectrometer is usually only a few tens of micrometers, so we need to focus the laser when performing Raman detection. This is very convenient for some applications, such as the need to study the cell bodies in natural gemstones. But in many cases, high focus also brings other problems.

For example: dark matter, because dark matter absorbs most of the laser power, it is easy to cause the sample to burn. There is a possibility of damage to the sample when measuring cultural relics and paintings. When measuring explosives such as black powder, potassium chlorate or potassium perchlorate, there is even a danger of direct detonation. As shown below

In addition, due to the focusing characteristics of Raman, only "point measurement" can be performed. For the analysis of some non-uniform samples, high focus is likely to lead to doubts about the representativeness of the detection spectrum. If the measured object is a non-uniform mixture, it is likely that there is no target at that point of measurement. For example, measuring a jade bracelet with a glue injection, but there is no glue on the measurement point, it may be mistaken for A cargo jade. When measuring a multi-component mixed solid drug, it is possible to measure only the edible auxiliary material and not the drug. As shown below

In response to this situation, some targeted technologies have emerged:

The first is the ORS moving spot technology, which avoids igniting objects by reducing the laser exposure time at a single location. However, since the micromechanical transmission structure is difficult to ensure that the trajectory of the spot is evenly distributed over a certain plane, the actual effect is that the spot is linearly "jittered" in a small range, and since the single point power density does not decrease, many In the case, the item will still be burned or even detonated, and the structure of the optomechanical structure of the device is very high, resulting in a decrease in reliability.

The second is TRS transmission technology. This technique requires a high sample size, requires a flaky sample, and is limited by the numerical aperture. This method is not optically efficient and has a smaller measurement range.

The third type is the "large spot" technique using the non-focus method. Since the measurement is not performed on the focus point of the objective lens, the illumination spot is enlarged, but the principle of focus measurement is violated, resulting in a large loss of light collection efficiency, even if Adding a reflective cavity around to make up for it also loses at least an order of magnitude more optical efficiency.

Moreover, all of the above three technologies can only expand the spot range to the millimeter level, which is still too small in practical applications. Moreover, the latter two technologies also greatly lose optical collection efficiency, resulting in signal degradation and inability to effectively distinguish samples.

How can we obtain a large area of ​​Raman features and achieve a uniform distribution of laser power without sacrificing optical efficiency? The compound eye part is solved into a myriad of compound eyes, and each small eye can be independently imaged, and a higher field of view and a reaction speed are obtained by the compound eye structure insect. From the compound eyes of insects, we have gained a good revelation. Through the bionics of the compound eye, the scientist invented the "flying eye camera" with a 160-degree field of view that can simultaneously focus on different depths of the object.

If, like a compound eye, there are countless small lenses that focus on the excitation light at the same time, we can evenly distribute the excitation light into many parts in the focal plane of the lens. Each small lens is a separate optical system, and the spectrometer slit and sample excitation position constitute an object-like conjugate relationship. Due to the different positions of the lenslets, we can cover the detection points over a wide range and detect them, which solves the problem that Raman detection can only perform "point measurement".

This is the first MOEMS array spot detection technology introduced by Jianzhi Instruments. It not only solves the problem that the high focus of Raman spectroscopy is easy to cause the sample to burn, but also realizes the Raman detection technology from “point measurement” to “surface measurement”. Breakthrough. Based on its own component-level R&D and design capabilities, Jianzhi Instruments breaks through the design and process difficulties, optimizes the single lens used in traditional Raman, optimizes it into array microlens, and then optimizes the corresponding optical path system. The bionic MOEMS Raman probe extends the detection range to the order of centimeters! The spot energy is reduced by 1-2 orders of magnitude, and within the detection range, hundreds of focused spotes are evenly distributed; and each spot maintains a high numerical aperture, evenly without significantly reducing the receiving efficiency. The laser irradiation power is shared and the sample can be detected in a large area.

Especially when measuring dangerous samples, it is absolutely safe because the single point power is less than 5mw. Thoroughly eliminate Raman spectroscopy to burn damaged samples, or ignite the possibility of detonating dangerous goods! And while evenly distributing the laser power, maintaining the ultra-high Raman acceptance efficiency, the signal deterioration will not be correctly resolved due to the measurement of dark objects.

MOEMS array spot detection technology can solve the representative problems in the Raman detection of mixed samples such as drugs, and avoid the ablation of Raman spectroscopy for high absorptivity substances (such as black powder, ABS materials, etc.). The damage phenomenon solves the problem that the flammable target can not be directly detected by Raman technology, and at the same time innovatively realizes large-area Raman detection at low energy density, which is an innovative change to the traditional Raman detection technology. Jane Instruments is confident that MOEMS will be the norm for the next generation of portable Raman spectroscopy. Absolute safety guarantees will greatly expand the scope of application of Raman spectroscopy.

Jianzhi Instrument released the new technology at the on-site rapid inspection technology development summit forum and 2019 brief wisdom new product conference, which kicked off the underlying technical innovation of Raman fast inspection. In 2019, the new Easy-Raman EV series handheld Raman spectroscopy products will be equipped with MOEMS array spot detection technology, so stay tuned.