CN105892047A - Series rotating mirror device for producing optical delay lines - Google Patents

Abstract

The invention relates to a series rotating mirror device for producing optical delay lines. The technical problem that the existing optical delay line device has the disadvantages of long delay time, low scanning frequency, poor linearity and poor stability is solved. The series rotating mirror device comprises a laser, a wave plate, a beam splitter, a first reflecting mirror, a second reflecting mirror, a third reflecting mirror, a lens, a first rotating plane transmitting mirror, a second rotating plane transmitting mirror, a fourth reflecting mirror, and a fifth reflecting mirror. Laser light emitted by the laser passes through the wave plate, and is then divided by the beam splitter into two laser beams, namely, a laser beam 1 and a laser beam 2. The laser beam 1 continue to be transmitted in parallel through the wave splitter, sequentially passes through the first reflecting mirror, the second reflecting mirror and the third reflecting mirror, and then enters the lens. The laser beam 2 sequentially passes through the first rotating plane transmitting mirror, the second rotating plane transmitting mirror, the fourth reflecting mirror and the fifth reflecting mirror, and joins the laser beam 1 to enter the lens. The series rotating mirror device is widely used in an optical information processing system and in a time-resolved optical system.

Description

A kind of series connection rotating lens unit for producing optical delay line

Technical field

The present invention relates to a kind of optical delay line device, particularly relate to a kind of for producing optics The series connection rotating lens unit of delay line.

Background technology

Along with terahertz time-domain spectroscopic technology, Superfast time resolution rate spectral technique, optical coherence The field of optical detection such as chromatography imaging technique and optical pumping-Detection Techniques flourish, Abnormal important effect is served in the characteristic of research material.And optical delay line is in above-mentioned skill Art is with a wide range of applications.The most conventional optical delay line device is to utilize step mostly Entering motor drives the optical mirror on linear micro-displacement platform to produce, but this type of optical delay There is longer latencies in line, simultaneously because use the delay that machinery means produce, it is impossible to realize Quickly scanning；Also favorably change light path with motorized motions revolving cube, but it is by surface shape , there is scanning uneven in the restriction of shape, poor linearity, in rotary course, sweep limits is uncertain Etc. unsurmountable shortcoming.

In recent years, along with the development of optical technology, revolving spiral face reflecting mirror is utilized to realize Total-reflection type week, epistasis scanning means was widely used in generation optical delay line, rate of scanning Have relatively before with time delay and be greatly improved.

Summary of the invention

The present invention is to solve existing optical delay line device length time delay, rate of scanning low, The linearity and the technical problem of stationarity difference, it is provided that a kind of delay distance is big, rate of scanning is high, The linearity and stationarity good for producing the series connection rotating lens unit of optical delay line.

The technical scheme is that, including laser instrument, wave plate, beam splitter, the first reflecting mirror, Second reflecting mirror, the 3rd reflecting mirror, lens, the first Plane of rotation diaphotoscope, the second rotary flat Face diaphotoscope, the 4th reflecting mirror and the 5th reflecting mirror, the laser that laser instrument sends is after wave plate The device that is split is divided into two bundle laser, respectively laser beam one and laser beam two；Laser beam one is parallel Continue transmission by beam splitter, sequentially pass through the first reflecting mirror, the second reflecting mirror, the 3rd reflection Lens are entered after mirror；

The direction transmission that laser beam two is vertical along the transmission direction sending laser with laser instrument, successively Through the first Plane of rotation diaphotoscope, the second Plane of rotation diaphotoscope, sequentially pass through the most again Entrance lens are converged with laser beam one after four reflecting mirrors, the 5th reflecting mirror.

Preferably, the first Plane of rotation diaphotoscope and the placed angle of the second Plane of rotation diaphotoscope The most remaining.

Preferably, the first Plane of rotation diaphotoscope and the second Plane of rotation diaphotoscope are connected to Rotary shaft.

Preferably, also include that ccd sensor, laser beam one and laser beam two converge entrance lens Rear injection, and enter ccd sensor.

The invention has the beneficial effects as follows, it is possible to produce fast optical delay line, not only at scanning frequency In rate, more existing use electric stepper motor method is significantly improved, and time delay also contracts It is as short as picosecond magnitude, the linearity and stationarity more preferable.

Further aspect of the present invention, by the description of detailed description below, is able to clear Chu records on ground.

Accompanying drawing explanation

Fig. 1 is the structural representation of the present invention；

Fig. 2 is the structural representation of decay part.

Reference numeral illustrates:

1. laser instrument, 2. wave plate, 3. beam splitter, 4. the first reflecting mirror, 5. the second reflecting mirror, 6. the 3rd reflecting mirror, 7. lens, 8. the first Plane of rotation diaphotoscope, 9. the second Plane of rotation Diaphotoscope, 10. the 4th reflecting mirror, 11. first rotary shafts, 12. second rotary shafts, 13. the 5th Reflecting mirror, 14.CCD sensor.In figure, dotted line represents laser beam.15. first normals, 16. Incident ray, 17. first boost lines, 18. first refractive light, 19. second normals, 20. Emergent ray, 21. second boost lines, 22. second refraction light.

First Plane of rotation diaphotoscope 8 and the rotation arrow of the second Plane of rotation diaphotoscope 9 in Fig. 1 Head refers to two plane transmission mirrors the most clockwise or the most counterclockwise.

Detailed description of the invention

As it is shown in figure 1, laser instrument 1 sends beam of laser source, this lasing light emitter is through a wave plate Become after 2 and there is the laser of polarization direction again by a beam splitter 3 so that laser beam divides For orthogonal two bundle laser, respectively laser beam A and laser beam B, laser beam A conduct Reference light continues transmission parallel through beam splitter 3, is transmitting after the first reflecting mirror 4 reflection To the second reflecting mirror 5, again reflex to the 3rd reflecting mirror 6 via the second reflecting mirror 5, pass through 3rd reflecting mirror 6 reflects the tailing edge direction identical with the laser beam that LASER Light Source sends and enters thoroughly Mirror 7, afterwards imaging on ccd sensor 14.

Wave plate 2 and the opposing parallel setting of lens 7.

Laser beam B is vertically transmitted as delay flashlight after being branched away by beam splitter 3, Through the first Plane of rotation diaphotoscope 8, and the first Plane of rotation diaphotoscope 8 is with the first rotary shaft Along shown by arrow direction high speed rotating centered by 11, then through the second Plane of rotation diaphotoscope 9, And second Plane of rotation diaphotoscope 9 high along shown by arrow direction centered by the second rotary shaft 12 Speed rotates.Laser beam B is through the first Plane of rotation diaphotoscope 8 and the second Plane of rotation transmission Certain optical path difference (laser after the first Plane of rotation diaphotoscope 8 is produced after mirror 9 Bundle B produces displacement and optical path difference, through mutual with the first Plane of rotation diaphotoscope 8 placed angle Also displacement and optical path difference can be produced after the second remaining Plane of rotation diaphotoscope 9.), but due to First Plane of rotation diaphotoscope 8 coordinate with the special angle of the second Plane of rotation diaphotoscope 9 so that Laser beam B does not changes the direction of propagation after eventually through the second Plane of rotation diaphotoscope 9. Laser beam B transmission after the second Plane of rotation diaphotoscope 9 is reflected to the 4th reflecting mirror 10 To the 5th reflecting mirror 13, the 5th reflecting mirror 13 receives and changes the transmission direction of laser beam B, The entrance lens 7 (laser beam B that the 5th reflecting mirror 13 reflects finally is converged with laser beam A Vertical with the transmission direction of laser beam A), eventually through ccd sensor 14 imaging.

Wave plate 2 is vertical with the transmission direction of the laser that laser instrument 1 sends.Wave plate 2 simply transmission Laser, the laser that laser instrument 1 sends transmits simply by wave plate 2, and transmission direction does not occurs Changing, beam splitter 3 is used to light splitting.

For the relatively sharp optical delay line process illustrating generation, special that theoretical derivation is clear and definite As follows:

As in figure 2 it is shown, the angle that incident ray 16 (i.e. laser beam B) is with angle of incidence as θ enters Inject the first Plane of rotation diaphotoscope 8, the refractive index definition of the first Plane of rotation diaphotoscope 8 For n, the thickness of the first Plane of rotation diaphotoscope 8 is defined as L, defines symbol △₁For laser beam B is by optical path difference produced by the first Plane of rotation diaphotoscope 8, and definition laser beam B is by the The most relatively and laser beam B incides the first Plane of rotation diaphotoscope to one Plane of rotation diaphotoscope 8 Displacement difference produced by the direction of 8 is X₁。

The refractive index of the second Plane of rotation diaphotoscope 9 and the refraction of the first Plane of rotation diaphotoscope 8 Rate is identical, the thickness of the second Plane of rotation diaphotoscope 9 and the thickness of the first Plane of rotation diaphotoscope 8 Spend identical, from the laser beam B of the first Plane of rotation diaphotoscope 8 outgoing with incident with laser beam B Identical to the angle of incidence angle of the first Plane of rotation diaphotoscope 8, define symbol △₂For laser beam B By optical path difference produced by the second Plane of rotation diaphotoscope 9.Definition △ is that laser beam B is passed through Light path total produced by first Plane of rotation diaphotoscope 8 and the second Plane of rotation diaphotoscope 9 Difference.

Definition laser beam B is by relatively entering with laser beam B after the second Plane of rotation diaphotoscope 9 Being mapped to displacement difference produced by the direction of the first Plane of rotation diaphotoscope 8 is X₂。

Laser beam B is through the first Plane of rotation diaphotoscope 8, the angle refraction with angle of incidence as θ Entering the first Plane of rotation diaphotoscope 8, the relative incident ray 16 of emergent ray 20 produces displacement Amount X₁, in the triangle relation being made up of the first normal 15 and the first boost line 17, obtain Incident ray 16 is produced optical path difference after outgoing.

The law of refraction according to light has:

Sin θ=nsin θ ＇ (1)

According to trigonometric function relational expression, when laser beam B is by the first Plane of rotation diaphotoscope 8, Relatively with lens without spin produced by optical path difference be:

${\mathrm{\Δ}}_1=\frac{L}{\cos \mathrm{\θ}}-\frac{L}{{\mathrm{cos\θ}}^{\′}}---\left(2\right)$

And after now laser beam B passes through the first Plane of rotation diaphotoscope 8 again, emergent ray phase There is a displacement difference for incident ray, according to trigonometric function relational expression, this displacement difference is:

$x_1=\frac{L}{{\mathrm{sin\θ}}^{\′}}-\frac{L}{\sin \mathrm{\θ}}---\left(3\right)$

The direction of this displacement is as shown in Figure 2.

In like manner, when the laser beam after the first Plane of rotation diaphotoscope 8 outgoing is again through the second rotation After turning plane transmission mirror 9, produced optical path difference is:

${\mathrm{\Δ}}_2=\frac{L}{\cos \mathrm{\θ}}-\frac{L}{{\mathrm{cos\θ}}^{\′}}---\left(4\right)$

Displacement produced by laser beam is:

$x_2=\frac{L}{{\mathrm{sin\θ}}^{\′}}-\frac{L}{\sin \mathrm{\θ}}---\left(5\right)$

But after laser beam B is by the second Plane of rotation diaphotoscope 9, owing to second rotates Plane transmission mirror 9 position relationship the most special with the first Plane of rotation diaphotoscope 8 so that its The most produced direction of displacement and laser beam B are by the side after the first Plane of rotation diaphotoscope 8 To on the contrary, simultaneously because the parameter of the second Plane of rotation diaphotoscope 9 and the first Plane of rotation transmission The parameter of mirror 8 is identical, therefore relative to incoming laser beam B, now outgoing beam and its Displacement is zero.The transmission direction of laser beam B does not changes.Transmission is being rotated through twice After mirror, optical path difference total produced by laser beam B is:

$\mathrm{\Δ}={\mathrm{\Δ}}_1+{\mathrm{\Δ}}_2=2(\frac{L}{\cos \mathrm{\θ}}-\frac{L}{{\mathrm{cos\θ}}^{\′}})=2L(\frac{1}{\cos \mathrm{\θ}}-\frac{1}{{\mathrm{cos\θ}}^{\′}})---\left(6\right)$

Formula (1) and trigonometric function relational expression are brought into formula (6), and according to mathematics triangle letter Number simplified formula obtains:

$2L(\frac{1}{\cos \mathrm{\θ}}-\frac{1}{{\mathrm{cos\θ}}^{\′}})=2L(\frac{1}{\sqrt{1-{\sin }^2\mathrm{\θ}}}-\frac{1}{\sqrt{1-{\left(\frac{\sin \mathrm{\θ}}{n}\right)}^2}})---\left(7\right)$

In formula (7), sin θ and sin θ/n are always less than 1, to radical sign in formula (7) Part is done Taylor expansion and is obtained:

$\sqrt{1-{\sin }^2\mathrm{\θ}}=1-\frac{1}{2}{\sin }^2\mathrm{\θ}-\frac{1}{8}{\sin }^4\mathrm{\θ})-\mathrm{...}-\frac{1}{n!}\frac{(2n-3)!!}{2^n}{\sin }^{2n}\mathrm{\θ}+R\left(x\right)---\left(8\right)$

$\sqrt{1-{\left(\frac{\sin \mathrm{\θ}}{n}\right)}^2}=1-\frac{1}{2}\frac{{\sin }^2\mathrm{\θ}}{n^2}-\frac{1}{8}{\left(\frac{{\sin }^2\mathrm{\θ}}{n^2}\right)}^2-\mathrm{...}-\frac{1}{n!}\frac{(2n-3)!!}{2^n}{\left(\frac{{\sin }^2\mathrm{\θ}}{n^2}\right)}^n+R_n\left(x\right)---\left(9\right)$

Wherein: n=2,3,4 ..., R (x) and R_nX () is respectively the remainder of corresponding expansion.

By error produced during high-order approximation and the convergence knowledge of remainder, by (8), (9) Formula arranges for people (7) formula:

Δ=(2n+1) Lsin²θ (10)

The above, only to the preferred embodiments of the present invention, is not limited to the present invention, For a person skilled in the art, the present invention can have various modifications and variations.Every In the range of the claim of the present invention limits, any modification, equivalent substitution and improvement etc. done, All should be within protection scope of the present invention.

Claims (4)

1., for producing a series connection rotating lens unit for optical delay line, it is characterized in that, Including laser instrument, wave plate, beam splitter, the first reflecting mirror, the second reflecting mirror, the 3rd reflecting mirror, Lens, the first Plane of rotation diaphotoscope, the second Plane of rotation diaphotoscope, the 4th reflecting mirror and Five reflecting mirrors, the laser that described laser instrument the sends device that is split after described wave plate is divided into two bundles Laser, respectively laser beam one and laser beam two；Described laser beam one continues parallel through beam splitter Resume defeated, enter after sequentially passing through described first reflecting mirror, the second reflecting mirror, the 3rd reflecting mirror Described lens；

The direction that described laser beam two is vertical along the transmission direction sending laser with described laser instrument Transmission, sequentially passes through described first Plane of rotation diaphotoscope, the second Plane of rotation diaphotoscope, so After sequentially pass through the 4th reflecting mirror, the 5th reflecting mirror again after with laser beam one converge entrance described Mirror.

Series connection revolving mirror dress for producing optical delay line the most according to claim 1 Put, it is characterized in that, putting of described first Plane of rotation diaphotoscope and the second Plane of rotation diaphotoscope Angle setting degree is remaining mutually.

Series connection revolving mirror dress for producing optical delay line the most according to claim 2 Putting, it is characterized in that, described first Plane of rotation diaphotoscope and the second Plane of rotation diaphotoscope are respectively Connect and have rotary shaft.

Series connection revolving mirror dress for producing optical delay line the most according to claim 3 Put, it is characterized in that, also include that ccd sensor, described laser beam one and described laser beam two converge Close and penetrate after entering lens, and enter described ccd sensor.