8 results about "Modulation spectroscopy" patented technology

The low-noise atom modulation spectrum detection system comprises a signal generator, sine wave signals generated by the signal generator are divided into two paths, one path is output to a laser device, and laser with modulation information is modulated in a current control mode; and the other path provides a reference signal for demodulation of the lock-in amplifier, the output laser is divided into pump light and probe light to ensure generation of saturated fluorescence in the rubidium atom steam chamber, then a low-noise silicon photoelectric detector is used for detecting a saturated fluorescence signal, and the lock-in amplifier demodulates and outputs the modulated saturated fluorescence signal. And meanwhile, a detection path of the saturated absorption spectrum is reserved, so that comparison with a modulated saturated fluorescence spectrum signal is facilitated. According to the invention, the requirement on the size of the atom steam chamber is obviously reduced, and the method is suitable for the application scenes of the Suppler spectrum, such as high-sensitivity, low-noise, anti-interference and miniaturized laser frequency stabilization and atom hyperfine structure detection.

A method of determining an optical spectrum for a sample substance includes splitting a source beam into a reference beam and a sample beam, periodically modulating the intensity of the beams out of phase of each other, directing the reference beam through a reference substance and the sample beam through the sample substance. The beams are then recombined, and a single detector detects the intensity difference at the modulation frequency to determine the spectrum of the sample substance.

This application provides a gas detection system and method based on near-infrared wavelength modulation and mid-infrared pulsed laser synergy, relating to the fields of spectroscopic gas detection and industrial flue gas monitoring. In industrial sites such as biomass power plants, hazardous waste incineration plants, and aluminum smelters, the flue gas generated in their flues has complex compositions. Traditional chemical detection methods are insufficient to meet real-time requirements, while other optical detection methods, such as Fourier transform infrared spectroscopy and ultraviolet differential spectroscopy, suffer from high costs and difficulty in avoiding water vapor interference. To address this, a system and method for detecting the concentration of gaseous pollutants in industrial flue gas based on near-infrared wavelength modulation and mid-infrared pulsed laser synergy is proposed. This system combines near-infrared wavelength modulation spectroscopy with mid-infrared pulsed direct absorption spectroscopy, employing multiple near-infrared tunable continuous lasers and mid-infrared tunable pulsed lasers. It utilizes time-division multiplexing and polling modes, combined with a common optical path design, to achieve real-time online monitoring of the concentration of various gaseous pollutants, ultimately significantly reducing the overall system cost.

This invention discloses a high-precision gas parameter measurement system and method based on the harmonic reconstruction principle, belonging to the field of data processing technology. The method includes the following steps: S1, processing the modulated transmittance signal to obtain harmonic curves from order 0 to k0; S2, obtaining the variation curves of each order harmonic with respect to the laser frequency based on the laser frequency variation signal and the harmonic curves from order 0 to k0; S3, determining the molecular absorption spectrum based on the variation curves of each order harmonic with respect to the laser frequency; S4, analyzing the molecular absorption spectrum to determine the physical parameters of the gas being measured. This invention retains the core advantages of wavelength modulation spectroscopy, such as high signal-to-noise ratio, strong anti-interference capability, and high measurement accuracy, while providing a new measurement method for high-precision calibration of spectral physical parameters, high-precision measurement of gas parameters under weak absorption conditions, and gas monitoring in complex industrial environments, effectively expanding the measurement efficiency and application scope of this technology.

A Microfluidic Modulation Spectroscopy (e.g. MMS) system enables measurement of a liquid analyte with a weak absorbance in a prescribed reference solution with a very high absorbance. The method includes alternatively flowing the liquid analyte and the prescribed reference solution through a fluid chamber in a liquid flow cell. The temperature of the analyte can be changed following a predetermined curve while spectral data is being collected. As the temperature of the analyte is increased, outgassing of trapped and dissolved air dissolved in the liquid analyte may be reduced, especially within the interrogation region of the flow cell, by application of a backpressure to the exit line of the flow cell. This is important for proteins, RNA, DNA, and other biomolecules because their structure and function are often temperature dependent. Further, some biological drugs need to be distributed globally and may encounter a range of ambient conditions in shipping.

A Microfluidic Modulation Spectroscopy (e.g. MMS) system enables measurement of a liquid analyte with a weak absorbance in a prescribed reference solution with a very high absorbance. The method includes alternatively flowing the liquid analyte and the prescribed reference solution through a fluid chamber in a liquid flow cell. The temperature of the analyte can be changed following a predetermined curve while spectral data is being collected. As the temperature of the analyte is increased, outgassing of trapped and dissolved air dissolved in the liquid analyte may be reduced, especially within the interrogation region of the flow cell, by application of a backpressure to the exit line of the flow cell. This is important for proteins, RNA, DNA, and other biomolecules because their structure and function are often temperature dependent. Further, some biological drugs need to be distributed globally and may encounter a range of ambient conditions in shipping.

The invention discloses a water vapor column concentration laser telemetering system and method based on TDLAS-WMS. The system comprises an electronics control unit, a laser modulator, a near-infrared laser, a collimator, a dichroscope, a first reflector, a second reflector, an optical convergence telescope, a narrow-band filter, a detector, a ranging radar and a visible light laser. According to the invention, the TDLAS-WMS-2f / 1f technology is used, and high-precision and high-stability water vapor column concentration measurement is realized. The tunable semiconductor laser absorption spectrum is combined with the wavelength modulation spectrum technology, signal processing is carried out according to the ratio of second harmonics to first harmonics, and interference caused by light intensity fluctuation, atmospheric turbulence and non-absorption loss in the light path transmission process can be effectively eliminated.