CN1804586A - Method for precisely measuring incident angle by means of laser feedback and application thereof - Google Patents
Method for precisely measuring incident angle by means of laser feedback and application thereof Download PDFInfo
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- CN1804586A CN1804586A CN 200510100839 CN200510100839A CN1804586A CN 1804586 A CN1804586 A CN 1804586A CN 200510100839 CN200510100839 CN 200510100839 CN 200510100839 A CN200510100839 A CN 200510100839A CN 1804586 A CN1804586 A CN 1804586A
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Abstract
The invention provides a method for using laser feedback to ascertain the enlarged dash with high accurate, which rotates the laser light source or plane interface opposed dash point to enlarged dash 0 deg. location along the enlarged dash reducing direction and keeps the light beam in the same dash surface when rotating it, it measures the reflecting light curve which is changed with the change of the enlarged dash; it spreads out the curve on the drawing software in the range of 0 deg., the laser feedback makes the output light intensity to generate flucticulus, it ascertains the wave bottom point as 0 deg. reference angle; it then uses the displacement of one point relative to 0 deg. reference angle to multiply with the length to obtain the corresponding enlarged dash.
Description
Technical field
The present invention relates to optical detective technology, particularly a kind of method and application thereof that utilizes the laser feedback high precision to determine incident angle.
Background technology
Optical waveguide is basic parts important in the integrated optics.Be based upon the optical device on the plane light wave waveguide technology, have that cost is low, volume is little, be convenient to batch process, good stability and being easy to and advantage such as other device is integrated.At present, integrated optical device is being brought into play important effect in applications such as communication, military affairs, electric power, astronomy, sensing.The refractive index of planar optical waveguide and film thickness are the bases of design and fabrication fiber waveguide device, and therefore, high Precision Detection planar optical waveguide parameter has crucial research and using value.At present, the refractive index of detection plane optical waveguide and the technology of film thickness are the prism-coupled methods simultaneously, the basic comprising of prism-coupled measuring system as shown in Figure 1, it detects principle: employing prism-coupled method excites the guided mode in the waveguide, the incident light that enters prism is after the base of prism is reflected, from the another side outgoing of prism, by the detector measurement reflective light intensity; When the incident angle of light beam on the prism base satisfies coupling condition (this moment, this angle was called synchro angle), the incident light energy is converted into the energy of guided mode, reflective light intensity is die-offed, regulate the incident angle of light beam at prism surface, after incident light is perpendicular to the prism plane of incidence, the reflective light intensity curve of beginning measuring beam when the incident angle of prism surface changes, a trough that occurs on the curve is corresponding to a guided mode in the planar waveguide, measure the corresponding incident angle in trough place, can calculate the synchro angle and the effective refractive index of corresponding guided mode; Measure the incident angle of adjacent three guided modes, utilize the waveguide eigenvalue equation again, can calculate the refractive index and the thickness of waveguide film.In this measuring technique, determining of initial angle is one of key factor that influences measuring accuracy.At present, in the self-built prism-coupled test macro in various laboratories, 0 ° of reference angle determine that whether having entered light source emergent light hurdle with eye-observation by the hot spot of prism surface beam reflected carries out, this is a kind of easy method, but precision is not high; In commercial tester, for example, the Metricon of the U.S.
TMThe prism-coupled instrument SPA series of 2010 prism-coupled instrument and Korea S all has to be equipped with to be exclusively used in the automated calibration system of determining 0 ° of reference angle, has therefore obviously increased the cost of instrument.
Summary of the invention
The objective of the invention is to overcome the shortcoming of prior art, a kind of method of utilizing the laser feedback high precision to determine incident angle is provided, this method does not need 0 ° of reference angle calibration system, but the accuracy of detection that can make incident angle reaches the minimum explanation angle of corresponding rotatable parts in the instrument, thereby both improved accuracy of detection, but the production cost of lowering apparatus again.
Another object of the present invention is to provide a kind of above-mentioned application that utilizes the laser feedback high precision to determine the incident angle method.
Purpose of the present invention is achieved through the following technical solutions: a kind of method of utilizing the laser feedback high precision to determine incident angle, specifically be with beam of laser from incident angle more than or equal to 0 ° ± 4 ' the optional position begin incident, the direction that allows light source or planar interface reduce along incident angle relative to incidence point is rotated continuously by 0 ° of position, require simultaneously that incident beam remains in the same plane of incidence in the rotation process, and the incident angle variation range has comprised each angle of required measurement; Reflective light intensity curve when measuring the incident angle variation, after curve launched in mapping software, corresponding to incident angle be 0 ° ± 4 ' near the interval in, because laser feedback (can be entered the resonator cavity of laser instrument by the light hurdle by the prism surface beam reflected when beam of laser, to cause laser instrument output intensity and the variation of exporting light frequency) make output intensity produce trickle fluctuation, the minimum trough point in this interval is defined as 0 ° of reference angle; The rotation step number of certain point multiply by the step-length angle value with respect to the displacement of 0 ° of reference angle on the reflective light intensity curve, is the corresponding incident angle of this point on the curve.
Because the variation of light source output intensity lags behind the reflected light that enters light source, to same measurement point, other test condition of maintenance system is constant, averages to rotating the step number displacement that obtains clockwise and counterclockwise, the step-length angle value is multiply by in average step number displacement, is exactly the corresponding incident angle of this point.
Described mapping software is that Excel, Origin, Matlab or other have the software of similar functions.
The above-mentioned method of utilizing the laser feedback high precision to determine incident angle can be applicable to calculate the synchro angle and the effective refractive index thereof of each guided mode of planar waveguide, by the incident angle and the planar waveguide eigenvalue equation of adjacent three guided modes, can calculate the refractive index and the thickness of waveguide film.In addition, in other some optical detecting instruments and equipment, also relate to the mensuration of incident angle, for example, ellipsometer, angular instrument etc., to this, the inventive method also can be used effectively.Therefore, the present invention has using value preferably in optical detection.
The present invention has following advantage and effect with respect to prior art: (1) precision height; Utilize the precision of 0 ° of definite reference angle of the inventive method can reach the angle of minimum resolution of the corresponding rotatable parts of instrument, so can high-precision mensuration incident angle.In the prism-coupled system that the experimental teaching that the inventive method is applied to Shanghai Communications University and provides is used, the measuring accuracy of refractive index can reach ± and 0.0001; And, adopt conventional method for same measuring system, even experienced technician, measuring accuracy also can only reach ± and 0.001.(2) simple, convenient; Utilize the inventive method need not adopt 0 ° of special reference angle calibration system, simplified operational procedure, efficient is higher.(3) cost is low; Because the inventive method can realize the function of existing 0 ° of reference angle calibration system,, thereby can obviously reduce the production and the use cost of equipment, better economy so alternative fully its is applied to the field that may use.(4) applied range; The present invention can be used for relating to the technical field that incident angle is measured, so range of application is wider, and good market prospect.
Description of drawings
Fig. 1 uses the structural representation that prism-coupled of the present invention is measured planar waveguide synchro angle device.
Fig. 2 is the detected reflective light intensity curve map (clockwise) that changes with incident angle of detector.
Fig. 3 is 0 ° ± 4 ' regional reflex of incident angle intensity variations curve map.
Embodiment
The present invention is described in further detail below in conjunction with embodiment and accompanying drawing, but embodiments of the present invention are not limited thereto.
Embodiment 1
Fig. 1 shows and uses the concrete structure that prism-coupled method of the present invention is measured planar waveguide synchro angle device, as seen from Figure 1, described device comprises rotatable platform 1, laser instrument 2, polarizer 3, light hurdle 4, prism 5, detector 6, A/D converter 7, computing machine 8, stepper motor 9 assemblies such as grade, on rotatable platform 1, place on the planar waveguide 10 (planar waveguide is made of substrate and film above being attached to), the laser that laser instrument 2 sends sees through polarizer 3 and light hurdle 4 is incident to prism 5, by being incident to detector 6 after prism 5 reflections, detector 6 is connected with A/D converter 7 and computing machine 8, and the stepper motor 9 that drives platform 1 rotation is connected with computing machine 8 simultaneously.Utilize aforementioned means to realize that the concrete steps of the inventive method are: operating personnel send instruction by computing machine, allow stepping motor 9 control platforms 1 rotate, and platform 1 drives prism 5 and can rotate along clockwise direction; The pitching of the platform 1 of prism 5 is placed in fine tuning, makes catoptrical incident angle almost nil, and reflect luminous energy and enter light hurdle 4 fully this moment; When prism 5 rotates along clockwise direction, require simultaneously that incident beam remains in the same plane of incidence in the rotation process, after the detector received signal, after data processing, show the reflective light intensity curve on computers, as shown in Figure 2.Among the figure near the O point bogging down area of waveform enter the interval on light hurdle corresponding to flare, the waveform after this wayside signaling amplifies, as shown in Figure 3.The plane of incidence of the prism more accurate location vertical with incident light be minimum trough point O place in Fig. 3 just; After the reflective light intensity curve amplified in Origin software, read the step number that O point place electrode rotates step number and certain trough point place, algebraic sum by these two step numbers, the step-length angle value is multiply by in the i.e. step number of this trough point step number displacement of ordering with respect to O, be the corresponding incident angle of this guided mode, can calculate the synchro angle and the effective refractive index thereof of this guided mode by this incident angle; By the incident angle and the planar waveguide eigenvalue equation of adjacent three guided modes, can solve the refractive index and the thickness of film.Table 1 is the step number displacement of adjacent three guided modes of actual measurement, has measured three times.
Table 1
Embodiment 2
Present embodiment except that following characteristics with embodiment 1: to same measurement point, keep the test condition identical with embodiment 1, prism rotates in the counterclockwise direction, and table 2 is step number displacements of above-mentioned adjacent three guided modes of surveying, has measured three times.
Table 2
To averaging with the step number displacement that rotates counterclockwise clockwise of same pattern, the step-length angle value is multiply by in average step number displacement, is exactly the corresponding incident angle of this point.Present embodiment eliminated because the variation of light source output intensity lags behind the measuring error that reflected light brought that enters light source, thereby the result is more accurate by bidirectional measurement.Table 3 is refractive index and thickness (step-length angle value, 7.4013 * 10 of the mean value of step number displacement and the film that calculates thus
-4).
Claims (5)
1, a kind of method of utilizing the laser feedback high precision to determine incident angle, it is characterized in that: beam of laser is incident to planar interface, LASER Light Source or planar interface are passed through 0 ° of position of incident angle relative to incidence point along continuous rotation of direction that incident angle reduces, and in rotation process, keep incident light in the same plane of incidence, measure the reflective light intensity curve that changes with incident angle; After curve launched in mapping software, near the interval corresponding to 0 °, laser feedback made output intensity produce trickle fluctuation, and the point of the trough in this interval is defined as 0 ° of reference angle; Rotation step number with certain point on the reflective light intensity curve multiply by the step-length angle value with respect to the displacement of 0 ° of reference angle then, is the corresponding incident angle of this point on the curve.
2, the method for utilizing the laser feedback high precision to determine incident angle according to claim 1 is characterized in that: when laser incides planar interface, from incident angle more than or equal to ± 4 ' the optional position begin incident.
3, the method for utilizing the laser feedback high precision to determine incident angle according to claim 1, it is characterized in that: to same measurement point, keep other test condition constant, average to rotating the step number displacement that obtains clockwise and counterclockwise, the step-length angle value is multiply by in average step number displacement, is exactly the corresponding incident angle of this point.
4, the method for utilizing the laser feedback high precision to determine incident angle according to claim 1 is characterized in that: described mapping software is Excel, Origin, Matlab.
5, be applied to calculate the synchro angle and the effective refractive index thereof of each guided mode of planar waveguide according to each described method of utilizing the laser feedback high precision to determine incident angle of claim 1～4, utilize the planar waveguide eigenvalue equation, calculate the refractive index and the thickness of waveguide film.
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| Application Number | Priority Date | Filing Date | Title |
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| CNB2005101008393A CN100561197C (en) | 2005-10-28 | 2005-10-28 | Utilize laser feedback to determine the method and the application thereof of incident angle |
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| CNB2005101008393A CN100561197C (en) | 2005-10-28 | 2005-10-28 | Utilize laser feedback to determine the method and the application thereof of incident angle |
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| CN1804586A true CN1804586A (en) | 2006-07-19 |
| CN100561197C CN100561197C (en) | 2009-11-18 |
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Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100434862C (en) * | 2006-11-21 | 2008-11-19 | 暨南大学 | Method for measuring minute angle based on self-commix interference of laser and apparatus thereof |
| CN101033952B (en) * | 2007-01-19 | 2010-09-08 | 暨南大学 | Angle measurement method and device capable of distinguishing rotary direction of angle |
| CN105092529A (en) * | 2015-09-15 | 2015-11-25 | 宁波大学 | Measurement device and method of medium refractive index |
| CN109931885A (en) * | 2019-03-06 | 2019-06-25 | 华南师范大学 | A kind of device of precise measurement light beam incidence angle |
| CN111220621A (en) * | 2020-03-13 | 2020-06-02 | 上海御微半导体技术有限公司 | Chip inclined surface detection method |
| CN115218796A (en) * | 2022-08-29 | 2022-10-21 | 重庆市计量质量检测研究院 | DEABC method for detecting parameters of multilayer film based on in-situ common-angle SPR |
-
2005
- 2005-10-28 CN CNB2005101008393A patent/CN100561197C/en not_active Expired - Fee Related
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100434862C (en) * | 2006-11-21 | 2008-11-19 | 暨南大学 | Method for measuring minute angle based on self-commix interference of laser and apparatus thereof |
| CN101033952B (en) * | 2007-01-19 | 2010-09-08 | 暨南大学 | Angle measurement method and device capable of distinguishing rotary direction of angle |
| CN105092529A (en) * | 2015-09-15 | 2015-11-25 | 宁波大学 | Measurement device and method of medium refractive index |
| CN105092529B (en) * | 2015-09-15 | 2017-09-19 | 宁波大学 | The measurement apparatus and its measuring method of medium refraction index |
| CN109931885A (en) * | 2019-03-06 | 2019-06-25 | 华南师范大学 | A kind of device of precise measurement light beam incidence angle |
| CN109931885B (en) * | 2019-03-06 | 2024-03-26 | 华南师范大学 | Device for accurately measuring incidence angle of light beam |
| CN111220621A (en) * | 2020-03-13 | 2020-06-02 | 上海御微半导体技术有限公司 | Chip inclined surface detection method |
| CN111220621B (en) * | 2020-03-13 | 2023-04-04 | 上海御微半导体技术有限公司 | Chip inclined surface detection method |
| CN115218796A (en) * | 2022-08-29 | 2022-10-21 | 重庆市计量质量检测研究院 | DEABC method for detecting parameters of multilayer film based on in-situ common-angle SPR |
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|---|---|
| CN100561197C (en) | 2009-11-18 |
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