CN201368771Y - Broadband spectrometer - Google Patents

Abstract

The utility model provides a broadband spectrometer which is mainly applied in spectral analysis and measurement, as well as material structure analysis, optical absorption and reflection measurement, and industrial process control such as the fields of pyrometry and gas element analysis. The broadband spectrometer comprises a light source (1), a light collimating system, a polarizer (4), a polarization rotating sheet (5) comprising optically active substances, a polarization analyzer (6), a detector (8) and a data acquisition and control system (9); and the light collimating system comprises two prisms (2). The broadband spectrometer is characterized in that the light source (1), the light collimating system, the polarizer (4), the polarization rotating sheet (5) comprising the optically active substances, the polarization analyzer (6), a condensing prism (7) and the detector (8) are arranged in sequence on an optical path from the light source (1) to the detector (8). The broadband spectrometer provided by the utility model has the advantages of broad band, multiple channels and high flux.

Description

A kind of broad band light spectrometer

Technical field

The utility model relates to a kind of broad band light spectrometer based on the optical activity chromatic dispersion principle, be mainly used in spectral analysis and spectral measurement aspect, also can be used for the structure analysis of material and optical absorption and reflection measurement, industrial process is controlled as high temperature measurement and gas analysis of components field.

Background technology

Spectral analysis and spectral measurement are research topics that relates generally in engineering and the scientific research.The spectral range of widespread use is from ultraviolet, as seen to infrared waves.What ultraviolet to the spectrometer in the visible light wave scope adopted is grating and prism chromatic dispersion light splitting technology, and the infrared spectrometer employing is grating, prism chromatic dispersion and Mechelson, A. A. (Michelson) interferometer technique (Fourier transform spectrometer).But adopt cover optical-mechanical system or a mirror chromatic dispersion light splitting technology can not satisfy spectral measurement from ultraviolet to infrared waves.Advanced spectrometer need possess two advantages, i.e. multichannel advantage and high flux advantage.The multichannel advantage is for to measure all spectrum units simultaneously with a detector, and is suitable with the multi-channel measurement situation.The characteristic of multi-path also helps to improve signal to noise ratio (S/N ratio).The high flux advantage is to adopt the slit that will use on the common color dispersion-type instrument, therefore has the measurement sensitivity of bigger radiation flux and Geng Gao.Advanced spectrometer also must possess the characteristics of pin-point accuracy, high-resolution ability, wide spectral range and low stray radiation.Grating and prism chromatic dispersion light splitting technology do not possess multichannel advantage and high flux advantage.The Fourier transform spectrometer can all be delivered to the radiation in the whole wavelength coverage on the detector simultaneously, therefore possesses multichannel and high flux advantage.But the Fourier transform spectrometer that is based on the Michelson interferometer technology can only be confined to the infrared band scope.

The utility model content

The purpose of this utility model is to provide a kind of broad band light spectrometer based on the optical activity chromatic dispersion principle.

The purpose of this utility model is achieved through the following channels: a kind of broad band light spectrometer, it comprises polarization revolving fragment, analyzer, detector and the data acquisition control system that light source, light source colimated light system, polarizer, optically active substance constitute, the light source colimated light system is made up of two prisms, is arranged in order polarization revolving fragment, analyzer, optically focused prism and the detector that light source, light source colimated light system, polarizer, optically active substance formation are installed at light source to the light path of detector; The position of focal plane of two prisms is located in the sample cell centre, detector places the focal position of optically focused prism, described analyzer is made of polarizer, stepper motor and code-disc, and the angle scanning speed of computer control rotatory polarization device and step-length are also kept the light intensity of detector in mind.

Described spectrometer has two kinds and regulates operation format, and a kind of is that polarizer is fixed, the analyzer rotation; Another kind is the polarizer rotation, and analyzer is fixed.Light source adopts incoherent light source or coherent source.Detector adopts photomultiplier or photodiode.

The utility model broad band light spectrometer is a kind of Fourier transform spectrometer that can be used in ultraviolet to the broad band light spectrometry of infrared band.Compare the utility model with conventional prism chromatic dispersion technology and need not adopt the slit that to use on the color dispersion-type instrument, therefore have big radiation flux and high measurement sensitivity.It has broadband, high resolution, multichannel and high-throughout advantage.

Description of drawings

Below in conjunction with accompanying drawing the purpose of this utility model and realization approach are described in further detail:

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

Fig. 2 is a principle schematic of the present utility model;

Fig. 3 is another principle schematic of the present utility model;

Fig. 4 is the chromatic dispersion function of alpha-quartz specific rotation.

Embodiment

The utility model is a kind of broad band light spectrometer based on the optical activity chromatic dispersion principle, as shown in Figure 1, it comprises polarization revolving fragment 5, analyzer 6, detector 8 and the data acquisition control system 9 that light source 1, light source colimated light system, polarizer 4, optically active substance constitute, the light source colimated light system is made up of two prisms 2, it is characterized in that: be arranged in order polarization revolving fragment 5, analyzer 6, optically focused prism 7 and the detector 8 that light source 1, light source colimated light system, polarizer 4, optically active substance formation are installed at light source 1 to the light path of detector 8; The position of focal plane of two prisms 2 is located in sample cell 3 centres, described detector 8 places the focal position of optically focused prism 7, described analyzer 6 is made of polarizer 11, stepper motor and code-disc 10, and computing machine 9 is controlled the angle scanning speed and the step-length of rotatory polarization devices 6 and kept the light intensity of detector 8 in mind.

Detector 8 adopts photomultiplier or photodiode.It is laser that light source 1 adopts incoherent light source or coherent source.

The utility model provides a kind of broad band light spectrometer, its principle of work is that the light wave by light source 1 radiation forms the plane polarization light wave by polarizer 4 behind colimated light system, the plane polarization light wave has different plane of polarization rotation angle by the incident light wave of the polarization revolving fragment that is made of optically active material 5 back different wave lengths, places the analyzer 6 between polarization revolving fragment 5 and the detector 8 and writes down the transmission light intensity and the anglec of rotation of analyzer 6 can be carried out spectral measurement and spectral analysis by rotation.

As Fig. 2, shown in Figure 3, behind polarizer 4, the direction of vibration of light wave is parallel to the polarization direction of polarizer 4, the polarization revolving fragment 5 of plane polarization light wave by constituting by the transparent optical active material, if the thickness of polarization revolving fragment 5 is d, the normal direction of polarization revolving fragment 5 is parallel to the optical axis direction of optically active material, and the plane of polarization that sees through polarization revolving fragment 5 back transmission-polarizing light waves rotates with respect to the plane of polarization of incident light wave.Because optically active effect of dispersion, the incident light wave of different wave length λ has different plane of polarization rotation angle θ, is expressed as θ=ρ (λ) d, and ρ is a specific rotation in the formula, is the function of lambda1-wavelength.The analyzer 6 of one may command rotation is placed between the polarization revolving fragment 5 and detector 8 of light path.Angle when between the polarization direction of the polarization direction of analyzer 6 and polarizer 4 is The time, the angle of the polarization direction of analyzer 6 and transmitted light plane of polarization is

If wavelength is the light intensity of the incident light of λ is I ₀(θ).Transmission light intensity by analyzer 6 these wavelength of back is

Or

According to the intensity superposition principle, the intensity of detector 8 records is the summation of all wavelengths light intensity, is angle

Function Therefore

Can be expressed as following convolution form:

Fourier transform is got on last both sides to be obtained

By rotation analyzer 6 and recording angular

Can calculate the Fourier transform function of spectrum by following formula with the transmission light intensity

Right

The inverting of carrying out Fourier transform can obtain the spectrum I relevant with plane of polarization rotation angle θ ₀(θ), i.e. I0 (θ)=F ^-1[I ₀(φ)].Rotation angle θ is the single-valued function of wavelength X.Can calculate the wavelength relevant spectral function I corresponding by the chromatic dispersion function ρ (λ) of specific rotation and the one-tenth-value thickness 1/10 d of polarization revolving fragment 5 with rotation angle θ=ρ (λ) d ₀(λ).Alpha-quartz α-SiO ₂Be a kind of optical activity crystalline material commonly used, its specific rotation chromatic dispersion function ρ (λ) as shown in Figure 4.Specific rotation chromatic dispersion function ρ (λ) according to alpha-quartz can try to achieve the funtcional relationship between wavelength X and the rotation angle θ, is shown below:

$\mathrm{\λ}={[0.03896+0.13637\left(\frac{\mathrm{\θ}}{d}\right)-2.74129\×{10}^{-4}{\left(\frac{\mathrm{\θ}}{d}\right)}^2+4.39723\×{10}^{-7}{\left(\frac{\mathrm{\θ}}{d}\right)}^3-3.3064\×{10}^{-10}{\left(\frac{\mathrm{\θ}}{d}\right)}^4]}^{-\frac{1}{2}}$

The unit of formula medium wavelength λ is a micron, and the unit of rotation angle θ is degree, and the unit of the thickness d of polarization revolving fragment 5 is a millimeter.

By above-mentioned analysis as can be seen the utility model be a kind of Fourier transform spectrometer.Based on the structured flowchart of the broad band light spectrometer of optical activity chromatic dispersion principle as shown in Figure 1.Rotatable analyzer is made of polarizer, stepper motor and code-disc, and angle scanning speed and step-length by computer control analyzer 6.

The material that constitutes polarization revolving fragment 5 is solid state optics active substance and liquid optically active substance; Described solid state optics active substance is meant alpha-quartz α-SiO ₂, lithium iodate LiIO ₃, alpha-iodine acid α-HIO ₃, among cinnabar HgS, the tellurium Te any one, described liquid optically active substance is meant in liquid crystal and the sucrose solution any one.Liquid optically active substance is placed into and constitutes polarization revolving fragment 5 in the transparent glass vessels.

The detecting band scope that depends on the thickness of operating wavelength range, optically active material of radiation spectrum scope, prism 2 and the polarizer 11 of light source and transparent wavelength scope, detector 8 based on the frequency band of detection width of the broad band light spectrometer of optical activity chromatic dispersion principle.For alpha-quartz crystal commonly used, its transparent wavelength scope is 0.18 to 3.6 micron.Resolution of the present utility model depends on the step value of analyzer rotation.If adopt stepper motor and 24 s' code-disc 10, the resolution of the anglec of rotation can reach 4 * 10 ^-5Degree.The angle scanning scope of stepper motor driven analyzer is 360 degree.Also can change resolution of the present utility model by the thickness d that changes optically active material.

Described spectrometer has two kinds and regulates operation format, and a kind of is that polarizer 4 is fixing, analyzer 6 rotations; Another kind of polarizer 4 rotations, analyzer 6 is fixing.Adopt the Fourier transform spectrometer of Michelson interferometer technology to be based on principle of optical interference, and the utility model is based on the optical activity chromatic dispersion principle.Rotation analyzer 6 in the utility model substitutes based on the index glass in the Fourier transform spectrometer of Michelson interferometer technology.Compare the utility model with conventional prism chromatic dispersion technology and need not adopt the slit that to use on the color dispersion-type instrument, therefore have big radiation flux and high measurement sensitivity.The broad band light spectrometer has broadband, multichannel and high-throughout advantage.Adopt stepper motor and code-disc 10 technology, the utility model can be realized computer control and measure at a high speed.

Claims (4)

1. broad band light spectrometer, it comprises polarization revolving fragment (5), analyzer (6), detector (8) and the data acquisition control system (9) that light source (1), light source colimated light system, polarizer (4), optically active substance constitute, the light source colimated light system is made up of two prisms (2), it is characterized in that: be arranged in order polarization revolving fragment (5), analyzer (6), optically focused prism (7) and the detector (8) that light source (1), light source colimated light system, polarizer (4), optically active substance formation are installed at light source (1) to the light path of detector (8); The position of focal plane of two prisms (2) is located in sample cell (3) centre, detector (8) places the focal position of optically focused prism (7), described analyzer (6) is made of polarizer (11), stepper motor and code-disc (10), and computing machine (9) is controlled the angle scanning speed and the step-length of rotatory polarization device (6) and kept the light intensity of detector (8) in mind.

2. a kind of broad band light spectrometer as claimed in claim 1 is characterized in that: described spectrometer has two kinds and regulates operation format, and a kind of is that polarizer (4) is fixing, analyzer (6) rotation; Another kind is polarizer (4) rotation, and analyzer (6) is fixing.

3. a kind of broad band light spectrometer as claimed in claim 1 is characterized in that: light source (1) adopts incoherent light source or coherent source.

4. a kind of broad band light spectrometer as claimed in claim 1 is characterized in that: detector (8) adopts photomultiplier or photodiode.

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