CN205450466U - Low light level signal reconsitution device based on surface plasma bistable state - Google Patents
Low light level signal reconsitution device based on surface plasma bistable state Download PDFInfo
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- CN205450466U CN205450466U CN201521132751.5U CN201521132751U CN205450466U CN 205450466 U CN205450466 U CN 205450466U CN 201521132751 U CN201521132751 U CN 201521132751U CN 205450466 U CN205450466 U CN 205450466U
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Abstract
The utility model belongs to the technical field of the reconsitution of low light level signal, a low light level signal reconsitution device based on surface plasma bistable state is provided to solve the drawback that prior art can't draw nanosecond level signal. The device includes signal source, polarization controller and feedback chamber. The feedback chamber comprises first beam splitter, second beam splitter, first speculum, the second mirror and kretschmann subassembly. First beam splitter setting is in polarization controller's output light path, and the kretschmann subassembly sets up on the transmitted light path of first beam splitter, and the second beam splitter sets up on the reflected light path of kretschmann subassembly, and first speculum setting is on the reflected light path of second beam splitter, and the second mirror sets up on the reflected light path of first speculum, and first beam splitter is located the second mirror's reflected light path simultaneously. The angle of incidence of the incident beam of kretschmann subassembly is 43.6 degrees~44.5 degrees.
Description
Technical field
This utility model belongs to the accidental resonance reconfiguration technique field of low light signals, is specifically related to a kind of based on surface plasma bistable low light signals reconstruct device.
Background technology
The low light level refers to that useful flashlight amplitude is the least relative to background noise, and the signal to noise ratio that receiving terminal receives is relatively low.In actual applications, optical signalling is often fallen into oblivion by background noise and is difficult to directly detect.In long-distance optical communication, the background noise interfering image has a variety of, the natural noise such as including lightning, thunderbolt, sudden and violent, the cosmic noise of atmospheric electricity, and the man-made noise such as between outer land signal, industrial lamp light radiation.These confusing interference factors all can cause the reduction of receiving terminal signal to noise ratio to make useful signal be difficult to be detected.Therefore, the non-linear amplification of the low light signals under strong noise background and signal to noise ratio lift technique have extremely important research and using value.Along with the continuous progress of science and technology, the range of application of Dim light measurement is the most broadly extended.Numerous military civil area such as laser radar, space optical communication, space-based target detection, optical remote sensing measurement, weather monitoring, track low-light cloud atlas in morning and evening, lll night vision, medical biotechnology electrical signal detection all proposes requirements at the higher level to the key technique of faint optics signal extraction Yu detection.Therefore, how effectively to have identified sequential signal from high intensity background noise, and adapt to various complex environment, response speed can reach nanosecond low light signals reconfiguration technique even faster has become low light level technology and application research and development key problem.
Due to characteristic and the effect of detection system intrinsic noise of background noise, mankind's exploration demand to macroscopic view with microcosmos the most gradually can not be fully met being filtered into main conventional low light signals detection mode.Traditional filtering mode is in the case of input signal-to-noise ratio is relatively low, it is obtained in that preferable signal extraction effect, but for being buried in the low light signals under strong noise background completely, or optical signal is identical with noise signal frequencies or close in the case of, helpless to be filtered into main conventional detection methods, therefore under research strong noise background, the reconstruct of low light signals is extremely urgent with enhancing.
People it is generally acknowledged that noise is harmful, and the biggest signal of noise is the poorest.But Stochastic Resonance Theory is pointed out, when containing noisy system generation accidental resonance, partial noise energy can be converted into useful signal energy, so that system output signal-to-noise ratio is greatly improved, can improve signal detection performance.Accidental resonance can realize the low light signals under strong noise background and extract, even if original noise and signal same frequency, the detection method institute that this point is conventional is irrealizable.Existing stochastic resonance method mainly includes two kinds: modulational instability and bistable state.But both of which must is fulfilled for three conditions just can be produced: nonlinear system, input modulating signal, noise source.These three condition can be met based on bistable accidental resonance technology, and the extraction of time-domain signal can be realized.But owing to mechanism of production is different, some bistable-state random resonance systems are merely able to be responsive to millisecond or second level signal, and the signal the most ultrafast for nanosecond is the most helpless.
Utility model content
Technical problem to be solved in the utility model be to provide a kind of speed of response up to nanosecond based on surface plasma bistable low light signals reconstructing method and device.
The technical solution of the utility model be provided based on surface plasma bistable low light signals reconstruct device include signal source, it is characterized in that and also includes: Polarization Controller and feedback cavity.Polarization Controller is arranged on the propagation path of input signal；Feedback cavity is made up of the first beam splitter, the second beam splitter, the first reflecting mirror, the second reflecting mirror and Kretschmann assembly, wherein the first beam splitter is arranged on the output light path of Polarization Controller, Kretschmann assembly is arranged on the transmitted light path of the first beam splitter, second beam splitter is arranged on the reflected light path of Kretschmann assembly, first reflecting mirror is arranged on the reflected light path of the second beam splitter, second reflecting mirror is arranged on the reflected light path of the first reflecting mirror, and the first beam splitter is positioned on the reflected light path of the second reflecting mirror simultaneously.It is provided with oscillograph on the transmitted light path of the second beam splitter.Kretschmann assembly is made up of prism, metal level and kerr medium the most successively, and wherein kerr medium is positioned at the bottom；The angle of incidence of the incident beam of Kretschmann assembly is 43.6 degree～44.5 degree.
Reducing for output signal time domain of the present utility model distortion, the angle of incidence of the incident beam of above-mentioned Kretschmann assembly is 43.9 degree；The metal layer thickness of Kretschmann assembly is that the width of 20nm, Kretschmann assembly and gross thickness are not less than the 1/2 of Kretschmann assembly lambda1-wavelength；Above-mentioned kerr medium is Sodium vapour.
(the reflection light of the i.e. second reflecting mirror incides incidence surface during the first beam splitter to the lower surface of above-mentioned first beam splitter, namely the first beam splitter is towards the side of Kretschmann assembly) it is coated with 500～600nm high-reflecting films, to reduce the transmitted intensity of the second beam splitter when the reflection light of the second reflecting mirror incides the second beam splitter, and then the energy loss of reduction feedback cavity inner light beam, improve delivery efficiency of the present utility model.
The splitting ratio of above-mentioned second beam splitter is 50:50.
The low light signals (transmitted light beam of the i.e. second beam splitter) that this utility model is reduced in order to make oscillograph receive the most completely, this utility model is provided with collimating lens in the light path between the second beam splitter and oscillograph.
This utility model uses the Kretschmann assembly being made up of prism, metal level and kerr medium, when TM polarized light incides Kretschmann assembly, the separating surface of its metal level and kerr medium produces evanescent wave, this evanescent wave along metal level and kerr medium interface propagate time along this interface excitating surface plasma, cause Kretschmann assembly that the reflectance of its incident illumination is changed, the Kretschmann assembly function that reflection coefficient is incident illumination light intensity (non-linear) to incident illumination, and then produce bistable-state random resonance；By being constituted feedback cavity by the first beam splitter, the second beam splitter, the first reflecting mirror, the second reflecting mirror and Kretschmann assembly, the reduction of the nanosecond low light signals fallen into oblivion by noise can be realized.
The utility model has the advantages that:
(1) simple in construction, light Louis are built, low cost；
(2) distortion of output signal time domain is little, there is not obvious delay phenomenon
This utility model can reduce the time domain distortion of output signal by the adjustment size of angle of incidence of Kretschmann assembly incident illumination, metal layer thickness.When the angle of incidence of Kretschmann assembly incident illumination be 43.9 degree, the thickness of metal level be 20nm time, the time domain distortion of output signal levels off to 0.
(3) scope that output signal of the present utility model is corresponding with the cross correlation measure gain of input signal is relatively big, and the signal intensity in input signal can realize the cross correlation measure gain output signal higher than 6 with noise intensity than for 1:5～1:30.
Accompanying drawing explanation
Fig. 1 is structural principle schematic diagram of the present utility model；
Fig. 2 a is that this utility model is at the input signal figure with very noisy；
Fig. 2 b is the Nanosecond pulse signal figure that this utility model extracts；
Wherein: 1-signal source；2-Polarization Controller；3-the first beam splitter；4-Kretschmann assembly；41-prism；42-metal level；43-kerr medium；5-the second beam splitter；6-the first reflecting mirror；7-the second reflecting mirror；8-collimating lens；9-oscillograph.
Detailed description of the invention
With detailed description of the invention, this utility model is further described below in conjunction with the accompanying drawings.
Signal source 1, Polarization Controller 2 and feedback cavity is included based on surface plasma bistable low light signals reconstruct device as it is shown in figure 1, provided by the utility model.Polarization Controller 2 is arranged on the propagation path of whole device input signal；Feedback cavity is made up of first beam splitter the 3, second beam splitter the 5, first reflecting mirror the 6, second reflecting mirror 7 and Kretschmann assembly 4, wherein the first beam splitter 3 is arranged on the output light path of Polarization Controller 2, Kretschmann assembly 4 is arranged on the transmitted light path of the first beam splitter 3, second beam splitter 7 is arranged on the reflected light path of Kretschmann assembly 4, first reflecting mirror 6 is arranged on the reflected light path of the second beam splitter 5, second reflecting mirror 7 is arranged on the reflected light path of the first reflecting mirror 6, and the first beam splitter 3 is positioned on the reflected light path of the second reflecting mirror 7 simultaneously.It is provided with oscillograph 9, the low light signals reduced for detection on the transmitted light path of the second beam splitter 5.Kretschmann assembly 4 is made up of prism 41, metal level 42 and kerr medium 43, wherein prism 41 is positioned at the Kretschmann assembly the superiors, metal level 42 is positioned at the intermediate layer of Kretschmann assembly, and kerr medium 43 is positioned at the bottom of Kretschmann assembly.Kerr medium 43 of the present utility model can use Sodium vapour.For producing bistable state resonance, the angle of incidence of the incident beam of Kretschmann assembly should be 43.6 degree～44.5 degree.
For making output signal time domain of the present utility model distortion be minimized (even if output signal and input signal phase contrast in time domain are minimized), the optimum of the angle of incidence of the incident beam of this utility model Kretschmann assembly 4 is 43.9 degree, the thickness of metal level 42 is that the width of 20nm, Kretschmann assembly 4 and gross thickness are not less than the 1/2 of Kretschmann assembly 4 lambda1-wavelength.
As optimization, this utility model is coated with 500～600nm high-reflecting films at the lower surface of the first beam splitter 3, to reduce the energy loss of feedback cavity inner light beam, improves the delivery efficiency (i.e. output signal strength/input signal strength) of whole device；The beam splitter using splitting ratio to be 50:50 is as the second beam splitter 5, and the delivery efficiency of device is maximum, up to 40%～50%.
The low light signals (transmitted light beam of the i.e. second beam splitter 5) that this utility model is reduced in order to make oscillograph 9 receive the most completely, this utility model is provided with collimating lens 8 in the light path between the second beam splitter 5 and oscillograph 9.
Operation principle of the present utility model and work process be:
From signal source 1 output signal (with the nanosecond pulse source of strong noise background) as whole device input signal enter Polarization Controller 2, Polarization Controller 2 for being changed into TM polarized light (because only that the incident beam of TM pattern can occur the Resonance Transmission enhancement effect of surface plasma, and the incident illumination of TE pattern will not occur this effect) by input signal.
TM polarized light incides on the first beam splitter 3, the transmitted light beam of the first beam splitter 3 is again incident on Kretschmann assembly 4, the incident beam of Kretschmann assembly 4 produces evanescent wave (particularly along being perpendicular to metal level 42 and kerr medium 43 interfacial direction generation evanescent wave) on the separating surface of metal level 42 and kerr medium 43, this evanescent wave along the separating surface of metal level 42 and kerr medium 43 propagate time just can excitating surface plasma, thus cause Kretschmann assembly 4 that the reflectance of its incident illumination is changed, and the nonlinear function that reflection coefficient is incident illumination light intensity.
The reflection light beam of Kretschmann assembly 4 is again incident on the second beam splitter 5, the reflection light beam of the second beam splitter 5 incides on the first reflecting mirror 6, the reflection light beam of the first reflecting mirror 6 incides on the second reflecting mirror 7, the reflection light beam of the second reflecting mirror 7 is finally again incident on the first beam splitter 3, such first beam splitter 3, Kretschmann assembly 4, second beam splitter 5, first reflecting mirror 6 and the second reflecting mirror 7 just constitute a feedback cavity, input signal is reduced to low light signals (transmitted light beam of the i.e. second beam splitter 5), the low light signals reduced incides on oscillograph 9 by collimating lens 8, detected by oscillograph 9.
The index evaluating this utility model extraction low light signals ability has two: cross correlation measure gain (unit: times) and snr gain (unit: dB), numerical value is the biggest, and the performance extracting low light signals is the best.The computational methods of the two index are:
(1) computational methods of cross correlation measure gain are:
X=<purified signal>and the cross correlation measure of<output signal>；
Y=<purified signal>and the cross correlation measure of<input signal>；
Cross correlation measure gain=x/y
(2) computational methods of snr gain are:
SNRInput=20*log (a1/a2)；
SNROutput=20*log (c1/c2)；
Snr gain=SNROutput-SNRInput
In formula, a1 is the maximum intensity of input signal；A2 is the substrate strength of input signal；C1 is the maximum intensity of output signal；C2 is the substrate strength of output signal.
Ability this utility model being extracted from a certain intensity noise background low light signals below in conjunction with Fig. 2 a and Fig. 2 b is described in detail (Fig. 2 a and Fig. 2 b can directly display from oscillograph).
Fig. 2 a is input signal of the present utility model, and wherein solid black curve a is the input signal containing very noisy, and black imaginary curve b is not by the purified signal of sound pollution；Fig. 2 b is output signal of the present utility model, and wherein solid black curve c is the Nanosecond pulse signal extracted.
Understand from Fig. 2 a and Fig. 2 b: a1=0.65, a2=0.54, c1=0.18, c2=0.015.
(1) this utility model is after the input signal shown in input Fig. 2 a, the cross correlation measure gain=x/y=corr2 of output signal and input signal (b, c)/corr2 (b, a)=0.7796/0.1126=6.9236 times.
Note: corr2 is by after curve data (i.e. Fig. 2 a and Fig. 2 b) the reading matlab software of oscilloscope display, calculates the universal command of cross correlation measure.
(2) this utility model is after the input signal shown in input Fig. 2 a, and the snr gain of output signal is:
Snr gain=SNROutput-SNRInput=20*log (c1/c2)-20*log (a1/a2)=20*log (0.18/0.015)-20*log (0.65/0.54)=45.99dB.
In sum, the cross correlation measure yield value of output signal of the present utility model and input signal is relatively big (up to more than 6 times), and the signal to noise ratio of output signal is close to 50dB.And the cross correlation measure yield value of the output signal of traditional bistable state resonator system and input signal is at 2 times～3 times, the signal to noise ratio of output signal is at 10dB～20dB.As can be seen here, than conventional bi-stable resonator system, this utility model extracts the advantage of low light signals under strong noise background.
Claims (7)
1. reconstruct device based on the bistable low light signals of surface plasma, including signal source；It is characterized in that: also include Polarization Controller and feedback cavity；Described Polarization Controller is arranged on the propagation path of input signal；Described feedback cavity is made up of the first beam splitter, the second beam splitter, the first reflecting mirror, the second reflecting mirror and Kretschmann assembly；Described first beam splitter is arranged on the output light path of Polarization Controller, described Kretschmann assembly is arranged on the transmitted light path of the first beam splitter, described second beam splitter is arranged on the reflected light path of Kretschmann assembly, described first reflecting mirror is arranged on the reflected light path of the second beam splitter, described second reflecting mirror is arranged on the reflected light path of the first reflecting mirror, and described first beam splitter is positioned on the reflected light path of the second reflecting mirror simultaneously；It is provided with oscillograph on the transmitted light path of described second beam splitter；Described Kretschmann assembly is made up of prism, metal level and kerr medium the most successively, and wherein kerr medium is positioned at the bottom；The angle of incidence of the incident beam of described Kretschmann assembly is 43.6 degree～44.5 degree.
It is the most according to claim 1 based on surface plasma bistable low light signals reconstruct device, it is characterised in that: the angle of incidence of the incident beam of described Kretschmann assembly is 43.9 degree.
The most according to claim 2 based on surface plasma bistable low light signals reconstruct device, it is characterized in that: the metal layer thickness of described Kretschmann assembly is that the width of 20nm, Kretschmann assembly and gross thickness are not less than the 1/2 of Kretschmann assembly lambda1-wavelength.
It is the most according to claim 3 based on surface plasma bistable low light signals reconstruct device, it is characterised in that: described kerr medium is Sodium vapour.
It is the most according to claim 4 based on surface plasma bistable low light signals reconstruct device, it is characterised in that: the lower surface of described first beam splitter is coated with 500～600nm high-reflecting films.
It is the most according to claim 5 based on surface plasma bistable low light signals reconstruct device, it is characterised in that: the splitting ratio of described second beam splitter is 50:50.
It is the most according to claim 6 based on surface plasma bistable low light signals reconstruct device, it is characterised in that: it is provided with collimating lens in the light path between described second beam splitter and oscillograph.
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| CN201521132751.5U CN205450466U (en) | 2015-12-30 | 2015-12-30 | Low light level signal reconsitution device based on surface plasma bistable state |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105467611A (en) * | 2015-12-30 | 2016-04-06 | 中国科学院西安光学精密机械研究所 | Weak light signal reconstruction device based on surface plasmon bistable state |
| CN106647330A (en) * | 2016-12-23 | 2017-05-10 | 核工业西南物理研究院 | Real-time plasma configuration reconstructing system and real-time plasma configuration reconstructing method for Tokamak |
-
2015
- 2015-12-30 CN CN201521132751.5U patent/CN205450466U/en not_active Withdrawn - After Issue
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105467611A (en) * | 2015-12-30 | 2016-04-06 | 中国科学院西安光学精密机械研究所 | Weak light signal reconstruction device based on surface plasmon bistable state |
| CN105467611B (en) * | 2015-12-30 | 2017-12-19 | 中国科学院西安光学精密机械研究所 | Based on the bistable low light signals reconstruct device of surface plasma |
| CN106647330A (en) * | 2016-12-23 | 2017-05-10 | 核工业西南物理研究院 | Real-time plasma configuration reconstructing system and real-time plasma configuration reconstructing method for Tokamak |
| CN106647330B (en) * | 2016-12-23 | 2019-09-17 | 核工业西南物理研究院 | A kind of Plasma shape real-time reconstructing system and method applied to tokamak |
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Granted publication date: 20160810 Effective date of abandoning: 20171219 |
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