English

Progress has been made in the development of anti resonant hollow core fiber Raman probes with low background noise at Shanghai Optics and Machinery Institute

474
2024-05-22 14:31:30
See translation

Recently, the research team of the Special Glass and Fiber Research Center of the Advanced Laser and Optoelectronic Functional Materials Department of the Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, aimed at the demand for in-situ detection of Raman signals, expanded the functions of the laboratory commercial Renishaw Invia confocal micro Raman spectrometer by using two independently designed and prepared anti resonant hollow core fibers (AR-HCFs) and external optical path modules, and added the in-situ detection function. The related achievements were published in Biomedical Optics Express under the title "In site background free Raman probe using double clamping anti resonant hollow core fibers".

Traditional quartz solid core optical fibers are widely used as probes for Raman detection due to their low loss and wide transmission window, making them ideal media for optical signals. When applied, although it can overcome the limitations of sample shape, size, and position, the interaction between the quartz glass material and the pump laser will generate a very strong background noise signal, which often masks the Raman spectral information of the test sample. In previous research reports, the mainstream solution was to use multiple fiber probes, utilizing different fibers to conduct excitation light and collect signal light. But this solution also requires adding optical components such as filters at the far end of the fiber optic, which not only reduces the efficiency of signal collection, but also increases the volume of the probe.

Researchers used the stack and draw method to manufacture two different double clad AR-HCFs, with cross-sections shown in Figure 1. They can mainly constrain the laser to conduct in the hollow core, greatly reducing the overlap between the optical field and the quartz material of the fiber itself, thereby greatly suppressing quartz background noise. After performance testing, the two fiber probes can achieve about two orders of magnitude of quartz background noise suppression compared to traditional solid core quartz fibers. Both AR-HCFs have been specially designed to achieve low loss in the visible and near-infrared bands, and have a larger numerical aperture (NA) in the outer layer (the NA of the outer layer is greater than 0.2, about ten times that of the fiber core). The characteristic of this work is to use only one fiber as the probe for Raman detection, and to combine the probe with the commercial Renishaw Invia confocal microscopy Raman spectrometer using a specially designed external optical path module, as shown in Figure 2. The module is connected to the original objective interface of the spectrometer, which can couple the excitation light emitted internally to AR-HCFs, and also transmit the Raman signal collected by the fiber optic probe back to the spectrometer for detection and analysis. While leveraging the high detection accuracy of the instrument, it can also expand its in-situ detection capabilities. The feasibility of the scheme was also verified by using probes to detect some solid and liquid samples, such as in-situ detection of ABS plastic, as shown in Figure 3. The research results are expected to have broader application prospects in fields such as environmental monitoring and biomedicine.

The electron microscope end face photos of two anti resonant hollow core optical fibers in Figure 1 are shown in (a) and (b), respectively, while (c) and (d) show photos of both taken by illuminating the back of the optical microscope.

Figure 2 Schematic diagram of Raman sensing scheme optical path.

Figures 3 (a) and (b) show the Raman spectra of two types of anti resonant hollow core fibers used as probes for detecting ABS plastic. The orange curve is obtained from the probe measuring the sample, the blue curve is the background signal of the probe itself, and the yellow curve is the spectrum directly measured by the Renishaw Invia confocal microscopy Raman spectrometer.

Source: Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences

Related Recommendations
  • LiDAR solutions provider Cepton acquired by KOITO

    On July 29, 2024, Cepton, a provider of high-performance LiDAR solutions, announced the signing of the final agreement for its acquisition, making it the acquiring company's subsidiary in the United States.Image source: CeptonAccording to the agreement, the acquirer is the internationally renowned automotive lighting giant KOITO, which was established in 1915 and has a history of over a hundred ye...

    2024-08-01
    See translation
  • Laser Wire Solutions and HumanTek Jointly Enter the Korean Laser Wire Stripping Market

    Recently, Laser Wire Solutions officially welcomed its important distribution partner in South Korea - HumanTek. This cooperation marks the official establishment of HumanTek as a branch of Laser Wire Solutions in Korea, and both parties will work together to provide excellent services for the Korean laser wire stripping market.HumanTek, with its deep foundation in the Korean market and strong pro...

    2024-07-03
    See translation
  • Focused Energy purchases two world-class high-energy lasers

    Recently, Focused Energy, a well-known foreign fusion energy startup, announced that it has officially signed an agreement to purchase two of the world's top high-energy lasers. These two large lasers will be deployed in the company's upcoming factory in the San Francisco Bay Area in the next two years.Scott Mercer, CEO of Focused Energy, stated, "These lasers are currently the highest average pow...

    2024-12-25
    See translation
  • BluGlass successfully raised $5.87 million to accelerate GaN laser production and delivery

    Recently, BluGlass, a leading global semiconductor development company, successfully completed its stock purchase plan (SPP) and raised $5.87 million in funds (excluding costs). This SPP provides eligible shareholders with the opportunity to subscribe to up to $100000 in new shares of BluGlass at a discounted price of $0.037 per share, along with free additional options. This initiative has gained...

    2024-04-12
    See translation
  • Researchers have manufactured chip based optical resonators that can operate in the ultraviolet (UV) and visible light regions of the spectrum

    Figure: Researchers have created a chip based ring resonator that operates in the ultraviolet and visible light ranges and exhibits record low UV loss. The resonator (small circle in the middle) is displayed as blue light.Researchers have created chip based photonic resonators that can operate in the ultraviolet (UV) and visible regions of the spectrum and exhibit record low UV loss. The ne...

    2023-10-06
    See translation