CN113820024A - Laser listener wavelength measurement experimental device and experimental method thereof - Google Patents

Abstract

The invention discloses a laser listener wavelength measurement experimental device and an experimental method thereof, wherein the experimental measurement device comprises an optical guide rail, a plurality of two-dimensional sliding seats, a laser, a polarizing plate group, a beam expander, a proportional-integral-pair lens, a micrometer eyepiece and a white screen; the experimental method sequentially comprises the steps of adjusting the equal height and the common axis, adjusting clear interference fringes, measuring the interference fringes of the reference light source and measuring the interference fringes of the light source to be measured. The invention has the beneficial effects that: the method applies the grammed-pair lens to the wavelength measurement of the laser listener, obtains the width of the cut-off part of the grammed-pair lens by measuring the distance of interference fringes, and calculates the laser wavelength; the experimental device is simple and convenient to operate, accurate in measurement and high in precision, and meanwhile, after the experimental device is further improved and improved, the experimental device can be used for detecting monochromatic light with specific wavelength generated by a multiband light source in crime scene investigation, is simple and convenient to operate, is high in measurement precision, and can be popularized and applied in a large area.

Description

Laser listener wavelength measurement experimental device and experimental method thereof

Technical Field

The invention relates to the technical field of experimental equipment, in particular to a laser listener wavelength measurement experimental device and an experimental method thereof.

Background

The laser listener plays an important role in actual combat, and the equipment performs photoelectric detection on received reflected laser and analyzes an acoustic signal through the steps of filtering, power amplification and the like, so that the functions of remote monitoring and sound source positioning are realized.

A semiconductor laser is a sensitive device, and the wavelength may drift due to the influence of factors such as environment and driving power during use. It has been found that, with a constant current, the output wavelength of the semiconductor laser increases as the temperature increases, with a variation of about 0.1-0.2 nm/deg.C. As a core component of the laser listener, the emission power and the emission wavelength stability of the semiconductor laser directly determine the actual combat effect of the laser listener. Especially, the emission wavelength of the laser emitter is closely related to the working frequency of electronic devices such as detection, filtering, modulation and demodulation, power amplification and the like in an analysis link in the laser listener, and the optimal listening effect can be realized only when the working frequencies are mutually matched.

In actual combat, along with the long-time work of laser listener or life's increase, receive the influence of factors such as self temperature and external environment, certain skew always can take place for the emission wavelength of semiconductor laser to lead to the unable effective matching that realizes operating frequency of the electron device of the analytic link of laser listener, seriously influence the listening effect. Therefore, the method has important significance for accurately measuring the emission wavelength of the semiconductor laser in real time, calibrating the working frequency of an electronic device in the analysis link of the laser listener in time and realizing the optimal listening effect.

The laser wavelength measurement problem is researched at home and abroad to a certain extent, and the laser wavelength measurement method mainly comprises the following steps: diffraction type and interference type. The diffraction type measurement precision is low; the interference type mainly includes: fizeau interference, fabry-perot interference and michelson interference. These interferometric measuring techniques have high accuracy, but the systems are complex and expensive, are mainly used as the measurement standard in the standard field, and are not suitable for being used as the wavelength measuring system of the laser detector.

Disclosure of Invention

In order to solve the existing problems, the invention designs a laser listener wavelength measurement experimental device and an experimental method thereof based on a proportional-integral-tangent lens.

A laser listener wavelength measurement experimental apparatus is based on the ratio of the cumulative tangent lens:

the laser listener wavelength measurement experimental device comprises an optical guide rail, a plurality of two-dimensional sliding seats, a laser, a polarizing plate group, a beam expander, a proportional-integral-pair lens, a micrometer eyepiece and a white screen;

the front surface of the optical guide rail is provided with a long scale, and two ends of the bottom of the optical guide rail are provided with lifting adjusting seats; the two-dimensional sliding bases can move left and right and are arranged on the optical guide rail; the laser, the polarization optical plate group, the beam expander, the differential integrator lens and the micrometer eyepiece are respectively arranged on the two-dimensional sliding seats; the laser comprises a helium-neon laser used as a reference light source and a semiconductor laser used as a light source to be detected.

The experimental method of the experimental device for measuring the wavelength of the laser listener comprises the following steps:

(1) adjusting the same height and the same axis. Placing a semiconductor laser with the wavelength of 532.0nm and a white screen on an optical guide rail with the length of 1.5m, opening the semiconductor laser, moving the white screen along the guide rail, and adjusting the laser direction until laser light spots all fall on small holes of the white screen when the white screen is moved on the whole guide rail, wherein the semiconductor laser beam is parallel to the optical guide rail;

taking down the semiconductor laser, placing a helium-neon laser with the wavelength of 632.8nm, and repeating the above operation steps to enable the helium-neon laser beam to be parallel to the optical guide rail;

and a polarizing plate group, a beam expander, a proportional-integral-pair lens and a micrometer eyepiece are sequentially placed on an optical guide rail from left to right, and the optical devices are respectively adjusted to be coaxial with the helium-neon laser at the same height.

(2) Clear interference fringes are called out. Remove the beam expander and make it place in the focus department than the cumulative pair of lenses, remove the micrometer eyepiece and place the real image interference zone of comparing the cumulative pair of lenses, utilize polarizing plate group to adjust the light intensity, observe the interference fringe in the visual field of micrometer eyepiece, for the convenience of measuring, after seeing clear interference fringe, should be with micrometer eyepiece front and back slow movement, make the interference fringe width appropriate.

(3) The interference fringes of the reference light source are measured. The helium-neon laser, the polarizing plate set, the beam expander, the proportional-integral-pair lens and the micrometer eyepiece are locked one by one, the micrometer eyepiece is used for measuring and reading and recording the position reading of 1 st to 21 st dark stripes, and attention is paid during measurement: the transverse line on the reticle is parallel to the interference fringe, and during measurement, the drum wheel can only rotate towards one direction, so that the generation of a space difference is prevented.

(4) And measuring the interference fringes of the light source to be measured. And replacing the helium-neon laser with a semiconductor laser, repeating the operation steps, and reading and recording the position readings of the 1 st to 21 st dark stripes by using a micrometer eyepiece.

The invention has the beneficial effects that: the method applies the grammed-pair lens to the wavelength measurement of the laser listener, obtains the width of the cut-off part of the grammed-pair lens by measuring the distance of interference fringes, and calculates the laser wavelength; the experimental device is simple and convenient to operate, accurate in measurement and high in precision, and meanwhile, after the experimental device is further improved and improved, the experimental device can be used for detecting monochromatic light with specific wavelength generated by a multiband light source in crime scene investigation, is simple and convenient to operate, is high in measurement precision, and can be popularized and applied in a large area.

Drawings

FIG. 1 is a schematic view of a grazing incidence lens;

FIG. 2 is a schematic diagram of a point light source S located on a central axis beyond the object focal plane of the paraxial pair of lenses;

FIG. 3 is a schematic diagram of a point source S located on a central axis within the object focal plane of the dyadic pair lens;

FIG. 4 is a schematic diagram of a point light source S located at the intersection of the object focal plane and the central axis of the dyadic pair lens;

FIG. 5 is an imaging optical path diagram of the upper half lens;

FIG. 6 is an interference pattern of two parallel beams of light;

FIG. 7 is a schematic diagram of an experimental apparatus for measuring wavelength of a laser sensor according to the present invention and an experimental method thereof;

FIG. 8 is an interference fringe image of a reference light source;

FIG. 9 is an interference fringe image of a light source to be measured;

FIG. 10 is a linear fit of the dark fringe positions of the reference light source interference pattern;

FIG. 11 is a linear fitting graph of the positions of the dark fringes of the interference pattern of the light source to be measured.

Detailed Description

The technical scheme of the invention is more fully explained in detail by combining the attached drawings.

In specific embodiment 1, an experimental apparatus and an experimental method for measuring a wavelength of a laser listener are based on a proportional-integral-tangent lens;

first, experiment principle

The phase-contrast tangential lens is an important element of many high-precision optical instruments, and has important significance in the fields of target identification, digital light calculation, optical information encryption and the like. The lens is formed by cutting off a part with the width a at the center (symmetrical about an optical center) of a convex lens along the diameter direction and splicing the remaining two parts, as shown in figure 1. After splicing, the optical center of the upper half lens is at O of a/2 below the spliced position₁The optical center of the lower half lens is at O of a/2 above the splice₂。

As shown in fig. 2, the point light source S is located on the central axis outside the object focal plane of the tangential lens, and the distance to the center O of the tangential lens is u, i.e., u < f. According to the lens imaging rule, the point light source forms a real image on the lens image side. Because the optical centers of the upper part and the lower part of the mischmetal lens are staggered, monochromatic light emitted by the point light source S is divided into two parts through the mischmetal lens and respectively converged at S₁And S₂And S is₁And S₂The two wave sources can be regarded as two new wave sources in the same wave front, and the coherence condition is met. Due to the reversibility of light, interference occurs in the overlapping region of two light waves.

As shown in fig. 3, the point light source S is located on the central axis within the object focal plane of the cumulative tangential lens, and the distance to the center O of the cumulative tangential lens is u, i.e., u < f. According to the imaging rule of the lens, the point light source forms a virtual image at the object space of the lens. Because the optical centers of the upper part and the lower part of the cumulative-tangential lens are staggered, monochromatic light emitted by the point light source S can be divided into two divergent spherical waves through the cumulative-tangential lens, two coherent virtual light sources S1 and S2 can be obtained in an object space after the monochromatic light passes through the cumulative-tangential lens, and the two virtual light sources interfere in a light wave overlapping area.

As shown in fig. 4, the point light source S is located at the intersection point of the focal plane of the object of the grazing incidence lens and the central axis, and the distance to the center O of the grazing incidence lens is u, i.e., u is f. Because than two parts optical centers stagger about the cumulative pair of section lens, the monochromatic light that pointolite S sent forms oblique decurrent parallel light at lens image space after first half lens refraction, through second half lens refraction back, forms oblique ascending parallel light at lens image space, can take place to interfere in two bundles of parallel light overlap regions, and the contained angle that two bundles of parallel light formed is theta.

Taking u as an example, theoretical derivation and experimental operation are carried out. Fig. 5 is an imaging optical path diagram of the upper half lens, wherein MN is the central axis of the grazing tangential lens, AB is the central axis of the original convex lens, and the rest of the original convex lens is complemented by a dotted line. Monochromatic light emitted by the point light source S is refracted by the lens to form parallel light, and the included angle formed between the parallel light and the central axis of the lens is 2/theta. The geometrical relationship shows that:

since the cut-off width a of the grazing cut lens is f, there is

Namely, it is

Fig. 6 is an interference diagram of two parallel light beams, where arrows indicate the propagation directions of the two parallel light beams, θ is the angle formed by the two parallel light beams, solid lines and dotted lines indicate the peak plane and the valley plane at a certain time in the interference region, X, Y, Z is the position of the bright fringe of constructive interference, D, E is the position of the dark fringe of destructive interference, and the perpendicular distance between two adjacent peak planes is the wavelength λ on the light screen PQ perpendicular to the central axis of the lens. According to the geometrical relationship, the following steps are carried out:

since a is f, there are

The distance between two adjacent dark stripes is as shown in formulas (2) and (3)

Second, experimental device

The laser listener wavelength measurement experimental device comprises an optical guide rail 1, a plurality of two-dimensional sliding seats 2, a laser 3, a polarizing optical plate group 4, a beam expander 5, a proportional integrator lens 6, a micrometer eye lens 7 and a white screen;

the front surface of the optical guide rail 1 is provided with a long scale 101, the two ends of the bottom of the optical guide rail are provided with lifting adjusting seats 102, and a plurality of two-dimensional sliding seats 2 can be arranged on the optical guide rail 1 in a left-right moving mode;

the laser 3, the polarizing plate group 4, the beam expander 5, the differential integrator lens 6 and the micrometer eyepiece 7 are respectively arranged on the two-dimensional slide bases 2, wherein the laser 3 comprises a helium-neon laser as a reference light source and a semiconductor laser as a light source to be detected.

Third, Experimental methods

(1) Adjusting the same height and the same axis. Placing a semiconductor laser with the wavelength of 532.0nm and a white screen on an optical guide rail with the length of 1.5m, opening the semiconductor laser, moving the white screen along the guide rail, and adjusting the laser direction until laser light spots all fall on small holes of the white screen when the white screen is moved on the whole guide rail, wherein the semiconductor laser beam is parallel to the optical guide rail;

taking down the semiconductor laser, placing a helium-neon laser with the wavelength of 632.8nm, and repeating the above operation steps to enable the helium-neon laser beam to be parallel to the optical guide rail;

and a polarizing plate group, a beam expander, a proportional-integral-pair lens and a micrometer eyepiece are sequentially placed on an optical guide rail from left to right, and the optical devices are respectively adjusted to be coaxial with the helium-neon laser at the same height.

(2) Clear interference fringes are called out. Remove the beam expander and make it place in the focus department than the cumulative pair of lenses, remove the micrometer eyepiece and place the real image interference zone of comparing the cumulative pair of lenses, utilize polarizing plate group to adjust the light intensity, observe the interference fringe in the visual field of micrometer eyepiece, for the convenience of measuring, after seeing clear interference fringe, should be with micrometer eyepiece front and back slow movement, make the interference fringe width appropriate.

(3) The interference fringes of the reference light source are measured. The helium-neon laser, the polarizing plate set, the beam expander, the proportional-integral-pair lens and the micrometer eyepiece are locked one by one, the micrometer eyepiece is used for measuring and reading and recording the position reading of 1 st to 21 st dark stripes, and attention is paid during measurement: the transverse line on the reticle is parallel to the interference fringe, and during measurement, the drum wheel can only rotate towards one direction, so that the generation of a space difference is prevented.

(4) And measuring the interference fringes of the light source to be measured. And replacing the helium-neon laser with a semiconductor laser, repeating the operation steps, and reading and recording the position readings of the 1 st to 21 st dark stripes by using a micrometer eyepiece.

Fourth, experimental measurement data and results

(1) Data measurement

In the experiment, the width a of the cut-off portion of the half-cut lens was measured by integrating the interference fringe pattern as shown in fig. 8 using a he — ne laser as a reference light source, and the measurement data of the dark fringe position are shown in table 1. The wavelength of an unknown light source is measured by using a semiconductor laser as a light source to be measured, the interference fringe pattern is shown in fig. 9, and the measurement data of the position of the dark fringe is shown in table 2.

TABLE 1 reference light source interference pattern dark fringe position measurement data

TABLE 2 measurement data of the position of the dark fringe of the interference pattern of the light source to be measured

(2) Data processing

Since the fringes of the interference pattern are equally spaced, X is satisfied_i＝X₀+△X·i, performing linear fitting on the measurement data of the dark fringe position of the interference pattern of the reference light source by utilizing origin software to obtain a graph 10, wherein delta X is the fringe distance, X₀The position of the 0 th order dark stripe.

According to the linear fitting result, the average distance of the dark stripes of the reference light source is known as follows:

the width of the cut part of the tangential lens

And performing linear fitting on the measurement data of the position of the dark fringe of the interference pattern of the light source to be measured by using origin software to obtain a graph 11.

According to the linear fitting result, the average distance of the dark stripes of the light source to be measured is as follows:

the wavelength of the light source to be measured can be obtained as follows:

(3) estimating uncertainty

According to the linear fitting result of the dark fringe position of the reference light source interference pattern, the standard error of the slope (i.e. the dark fringe distance Δ X of the reference light source interference pattern) is as follows:

the uncertainty of the dark fringe spacing of the reference light source interference pattern is:

u(Δx)＝4.92×10^-4mm；

according to the linear fitting result of the positions of the dark fringes of the interference pattern of the light source to be measured, the standard error of the slope (namely the distance delta x' between the dark fringes of the interference pattern of the light source to be measured) is as follows:

the uncertainty of the distance between the dark fringes of the interference pattern of the light source to be detected is as follows:

u(Δx)＝4.92×10^-4mm；

by the error transfer formula

To obtain

u(λ)＝3_.0nm；

The wavelength of the light source to be measured is:

the measurement result and the standard value lambda of the light source (semiconductor laser) to be measured_{Sign board}Compared with 532.0nm, the relative error epsilon is 2.0%.

The invention applies the grammed-pair lens to the wavelength measurement of the laser listener, and obtains the width of the cut-off part of the grammed-pair lens by measuring the distance of the interference fringes, thereby calculating the laser wavelength. The experiment is easy and convenient to operate, the measurement is accurate, and the precision is higher. Meanwhile, after the experimental device is further improved and improved, the experimental device can be used for detecting monochromatic light with specific wavelength generated by a multiband light source in crime scene investigation.

In the description herein, reference to the terms "one embodiment," "some embodiments," "an example," "a specific example," or "some examples" or the like means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the present invention, and any modifications, equivalents and improvements made within the spirit and principle of the present invention should be included in the scope of the present invention.

Claims (2)

1. The utility model provides a laser listener wavelength measurement experimental apparatus, is based on than the tired tangent lens, its characterized in that:

the laser listener wavelength measurement experimental device comprises an optical guide rail, a plurality of two-dimensional sliding seats, a laser, a polarizing plate group, a beam expander, a proportional-integral-pair lens, a micrometer eyepiece and a white screen;

the front surface of the optical guide rail is provided with a long scale, and two ends of the bottom of the optical guide rail are provided with lifting adjusting seats; the two-dimensional sliding bases can move left and right and are arranged on the optical guide rail; the laser, the polarization optical plate group, the beam expander, the differential integrator lens and the micrometer eyepiece are respectively arranged on the two-dimensional sliding seats; the laser comprises a helium-neon laser used as a reference light source and a semiconductor laser used as a light source to be detected.

2. The experimental method of the experimental device for measuring the wavelength of the laser listener according to claim 1, wherein: the method comprises the following steps:

(1) adjusting the same height and the same axis. Placing a semiconductor laser with the wavelength of 532.0nm and a white screen on an optical guide rail with the length of 1.5m, opening the semiconductor laser, moving the white screen along the guide rail, and adjusting the laser direction until laser light spots all fall on small holes of the white screen when the white screen is moved on the whole guide rail, wherein the semiconductor laser beam is parallel to the optical guide rail;

taking down the semiconductor laser, placing a helium-neon laser with the wavelength of 632.8nm, and repeating the above operation steps to enable the helium-neon laser beam to be parallel to the optical guide rail;

and a polarizing plate group, a beam expander, a proportional-integral-pair lens and a micrometer eyepiece are sequentially placed on an optical guide rail from left to right, and the optical devices are respectively adjusted to be coaxial with the helium-neon laser at the same height.

(2) Clear interference fringes are called out. Remove the beam expander and make it place in the focus department than the cumulative pair of lenses, remove the micrometer eyepiece and place the real image interference zone of comparing the cumulative pair of lenses, utilize polarizing plate group to adjust the light intensity, observe the interference fringe in the visual field of micrometer eyepiece, for the convenience of measuring, after seeing clear interference fringe, should be with micrometer eyepiece front and back slow movement, make the interference fringe width appropriate.

(3) The interference fringes of the reference light source are measured. The helium-neon laser, the polarizing plate set, the beam expander, the proportional-integral-pair lens and the micrometer eyepiece are locked one by one, the micrometer eyepiece is used for measuring and reading and recording the position reading of 1 st to 21 st dark stripes, and attention is paid during measurement: the transverse line on the reticle is parallel to the interference fringe, and during measurement, the drum wheel can only rotate towards one direction, so that the generation of a space difference is prevented.

(4) And measuring the interference fringes of the light source to be measured. And replacing the helium-neon laser with a semiconductor laser, repeating the operation steps, and reading and recording the position readings of the 1 st to 21 st dark stripes by using a micrometer eyepiece.

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