CN200986599Y - High efficient polarization converter - Google Patents

Abstract

The utility model provides a polarization switching device including a first prism and a second prism. The first prism includes an incident plane, a first reflecting plane, a second reflecting plane and an the emission plane. The second prism includes a refracting plane, a first reflecting plane and a second reflecting plane. The first reflecting plane and second reflecting plane of the first prism are mutually parallel with the refraction plane of the second prism. An included angle between the incident plane and the first reflecting plane of the first prism is equal with an included angle between the emission plane and the first reflecting plane of the first prism. The angle makes one part of the incident light reflect at the first reflecting plane of the first prism, the other part of the incident light generate perfect reflection which makes the light incident to the refraction plane of the second prism refract into the second prism at the refraction plane. The included angles of the two reflecting planes of the second prism and the are equal refraction plane are equal. The angle makes the incident light on the first reflecting surface of the second prism reflect along the direction parallel to the refraction surface of the second prism. The utility model makes fully use of the characteristics of crystal which can switch the single wavelength non-polarized light into polarized light high effectively in the case of low light intensity loss.

Description

The high-level efficiency polarization converter

Technical field

The utility model relates to optical device, relates in particular to a kind of high-level efficiency polarization converter to nonpolarized light.

Background technology

In laser and optical technical field, usually need polarization light output, this just need be converted to linearly polarized light with nonpolarized light, existing polaroid is two the mutually perpendicular directions that are projected in the nonpolarized light equivalence, obtain two light intensity and equate the vertical linearly polarized light of direction of vibration, then allow wherein a part of linearly polarized light pass through, eliminate the linearly polarized light of another part simultaneously by polaroid.The energy that this can waste another polarized component causes its polarization conversion efficiency low (intensity loss surpasses 50%), and the light of another polarized component that is wasted even might become background miscellaneous light, influences the performance of device.

The utility model content

For overcoming above-mentioned shortcoming, the invention provides a kind of polarization converter, it comprises first prism and second prism.First prism comprises a plane of incidence, first reflecting surface, second reflecting surface and exit facet, and second prism comprises plane of refraction, first reflecting surface and second reflecting surface.The plane of refraction of first reflecting surface of first prism, second reflecting surface of first prism and second prism is parallel to each other.The plane of incidence in first prism equates with the angle of first reflecting surface with the exit facet in first prism with the angle of first reflecting surface, this angle makes the part of incident light reflect at the first reflecting surface place of first prism, another part generation total reflection, and the feasible light that incides the plane of refraction of second prism is refracted into second prism at the plane of refraction place.Two reflectings surface in second prism equate with the angle of its plane of refraction, and this angle makes first reflecting surface of second prism make the light of incident on it along the direction reflection parallel with the plane of refraction of second prism.First prism is made of positive crystal or negative crystal.Second prism is made of in positive crystal, negative crystal and the isotropic material any.

In addition, in polarization converter of the present invention, the angle of the plane of incidence of first prism and first reflecting surface is set to: make to enter first prism with the luminous energy of being scheduled to incident angle incident, in first prism, reflect into two-beam, and total reflection takes place in wherein a branch of light then at the first reflecting surface place, another Shu Guang reflects at the first reflecting surface place, and the feasible light that incides the plane of refraction of second prism is refracted into second prism at the plane of refraction place.

In addition, in polarization converter of the present invention, the reflecting surface of second prism and the angle of its plane of refraction are set to: make the light that is refracted into second prism at the first reflecting surface place of second prism total reflection take place, and make through the direction propagation parallel with the plane of refraction of second prism of the light edge of total reflection.

In addition, above-mentioned polarization converter also comprises the compensator that the exit facet place of first prism is provided with.But the surface of passing through light of each optical device in above-mentioned polarization converter is the plating anti-reflection film all.

In addition, in polarization converter of the present invention, first reflecting surface of first prism is set to distance between second reflecting surface: thus two parts luminous energy that the light path symmetry in first prism is separated overlaps at the exit facet place of first prism.And the distance between the plane of refraction of first reflecting surface of first prism and second prism is set to: thus two parts luminous energy that the light path symmetry in second prism is separated overlaps at the exit facet place of first prism.

With general the comparing of adopting of prior art such as polarization devices such as polaroid and Brewster windows, the utility model makes full use of the characteristic of crystal, by the geometric configuration of prism is calculated and adjusted, can under the situation of extremely low light intensity loss, convert the nonpolarized light of importing to linearly polarized light efficiently.

Suppose that wavelength is that the laser of λ is 5% at the light intensity reflectivity on the surface of the prism of forming efficient polarization converter and the light intensity reflectivity that had the surface of deflection device now, so directly the light intensity by the linearly polarized light that obtains behind the full light intensity polarization converter is greater than 80% of the light intensity of incident nonpolarized light, and the light intensity of the linearly polarized light that obtains by existing deflection device is less than 47.5% of the light intensity of incident nonpolarized light; If each incident interface and outgoing interface at the high-level efficiency polarization converter use suitable anti-reflection film can obtain the linearly polarized light of light intensity greater than the light intensity 95% of incident nonpolarized light, and the light intensity utilization factor of existing deflection device can not surpass 50%.

Should be appreciated that the above generality of the utility model is described and the following detailed description all is exemplary and explanat, and be intended to provide further explanation for as claimed in claim the utility model.

Description of drawings

Comprise that accompanying drawing is for providing the utility model further to be understood, they are included and are constituted the application's a part, and accompanying drawing shows embodiment of the present utility model, and play the effect of explaining the utility model principle with this instructions.In the accompanying drawing:

Fig. 1 shows a kind of working condition of polarization converter of the present utility model.

Fig. 2 shows the another kind of working condition of polarization converter of the present utility model.

Fig. 3 shows two situations that prism connects airtight mutually among the embodiment 1.

Embodiment

As illustrated in fig. 1 and 2, polarization converter comprises prism A, prism B and compensator C.Prism A comprises the plane of incidence (ad), first reflecting surface (cd), second reflecting surface (ab) and exit facet (bc).Prism B comprises plane of refraction (ef), first reflecting surface (eg) and second reflecting surface (gf).Among the prism A, faceted pebble (ab) is parallel with faceted pebble (cd), faceted pebble (bc) equates (being ∠ bcd=∠ cda=θ ') with the angle and the faceted pebble (ad) of faceted pebble (cd) with the angle of faceted pebble (cd).Among the prism B, two fully reflecting surfaces (eg) of prism B and (gf) equate (being ∠ feg=∠ efg=β) with the angle of plane of refraction (ef).Prism A, B are separated from each other, and the reflecting surface of prism A (ab) and (cd) be parallel to the plane of refraction (ef) of prism B.Angle θ ' makes the part of incident light locate to reflect another part generation total reflection at first reflecting surface (cd) of prism A; And the feasible light that incides the plane of refraction of described second prism is refracted into described second prism at described plane of refraction place.Angle beta make first reflecting surface (eg) of prism B with the light of incident on it along the direction reflection parallel with the plane of refraction (ef) of prism B.

Unpolarized monochromatic light is injected prism A with incident angle θ, on the interface of prism A and air (cd), be divided into two parts, wherein a part of light continues to propagate in prism A, and another part light penetrates prism A and enter prism B and through penetrating prism A after twice total reflection from prism B penetrates and enter prism A and the light compositing of propagating among prism A after.

Embodiment under the various conditions of polarization converter of the present utility model is described below in conjunction with accompanying drawing.

Fig. 1 shows the situation that the less light of the refractive index ratio of the different polarization states of co-wavelength among the crystal A penetrates.Following embodiment 1 to 6 all is that accompanying drawing is described with Fig. 1, and these embodiment belong to the situation that the less light of refractive index ratio of the different polarization states of co-wavelength among the crystal A penetrates.

(embodiment 1)

With reference to figure 1, two prisms of present embodiment constitute by negative crystal, and wherein the optical axis direction of prism A is perpendicular to the plane of incidence (being paper) of incident light, and the optical axis direction of prism B is perpendicular to the plane of incidence (being paper) of incident light.The negative crystal material that constitutes prism A can be different with the negative crystal material that constitutes prism B.

If the unpolarized monochromatic wavelength of incident is λ, negative crystal A is that the o light of λ, the principal refractive index of e light are respectively n to wavelength _o ^-, $n_e^{-}=(n_o^{-}>n_e^{-}>1)$ , negative crystal B is that the o light of λ, the principal refractive index of e light are respectively n to wavelength _o' ^-, $n_e^{\′-}(n_o^{\′-}>n_e^{\′-}>1).$

1} negative crystal A preferably meets the following conditions:

(1) faceted pebble (ab):

[1]，

N wherein ₀The refractive index of expression air;

(2) angle of prism A:

[2]，

N wherein ₀The refractive index of expression air;

(3) faceted pebble (cd):

[3]，

N wherein ₀The refractive index of expression air;

2} negative crystal B preferably meets the following conditions:

(1) faceted pebble (ef):

[4]，

N wherein ₀The refractive index of expression air;

(2) angle of prism B:

$\sin \mathrm{\ψ}>\frac{n_0}{n_e^{\′-}},$

[5]，

N wherein ₀The refractive index of expression air;

When satisfying above condition, preferably meet the following conditions between prism A and the prism B:

$H=\frac{\stackrel{\‾}{\mathrm{mn}}}{2N}\cot \mathrm{\θ},$ N＝1，2，…… [6]，

The distance between the faceted pebble (ef) of the faceted pebble (cd) of H ' expression negative crystal A and negative crystal B wherein, H represents the seamed edge of negative crystal A

With seamed edge

Between distance.When H ', H meet above-mentioned condition simultaneously, will guarantee that two light path symmetries in the prism make two parts light can overlap at last synthesising position.

Can learn according to above all equatioies, the preferred span of angle θ ' need satisfy based on angle θ preferred span, this preferred span is intended to guarantee that (1) is refracted into prism A with the luminous energy that angle θ incides the plane of incidence of prism A, (2) incident optical energy after the refraction locates to take place part refraction and part total reflection at faceted pebble (cd), as shown in the figure, (3) make the light that light by faceted pebble (cd) outgoing incides the plane of refraction of described second prism be refracted into described second prism at described plane of refraction place.

Can learn according to above all equatioies, the preferred span of angle beta need satisfy based on angle θ preferred span, this preferred span is intended to guarantee that (1) incide the luminous energy of the faceted pebble of prism B (ef) and refraction takes place and enter prism B, (2) incident optical energy after the refraction locates to take place total reflection at faceted pebble (eg), and the light after (3) total reflection is propagated along the direction that is parallel to (ef).

(that is, the angle beta of the angle θ ' of prism A and prism B) scope all has in following all embodiment and relates to these architectural features, and it acts among each embodiment and all is equal to.

Unpolarized monochromatic light is divided into two bundles at the faceted pebble (ad) of prism A, two-beam is synthetic by the faceted pebble (bc) at prism A after the propagation of two prisms respectively, and synthesize only and form, but exist fixing phase differential between this two bunch polarized light by the orthogonal linearly polarized light in two bundle polarization directions.In order to make the only linearly polarized light of output, need be adjusted into according to the phase differential between two parts linearly polarized light after making synthetic light will synthesize shown in the figure by compensator C (being the Soleil compensator)

Φ＝iπ，i＝0，±1，±2…… [7]。

In addition, be to improve the utilization factor of light, can be on the plane of incidence of each prism and exit facet the corresponding anti-reflection film of plating, to improve the transmitance of light.

(modification 1)

Structure and the principle of the modification of embodiment 1 and embodiment 1 are basic identical, and difference is that the optical axis direction of negative crystal B in this modification is parallel to face efg (being paper).

Therefore, the formula in the foregoing description [4] becomes:

[8]，

Formula [5] becomes:

$\sin \mathrm{\ψ}>\frac{n_0}{n_o^{\′-}},$

[9]。

(embodiment 2)

With reference to figure 1, the prism A of present embodiment is made of negative crystal, and prism B is made of positive crystal.Wherein the optical axis direction of prism A is perpendicular to the plane of incidence (being paper) of incident light, and the optical axis direction of prism B is perpendicular to the plane of incidence (being paper) of incident light.The geometric configuration of embodiment 2 is identical with embodiment's 1, repeats no more.

If the unpolarized monochromatic wavelength of incident is λ, negative crystal A is that the o light of λ, the principal refractive index of e light are respectively z to wavelength _o ^-, $n_e^{-}(n_o^{-}>n_e^{-}>1),$ The wavelength of positive crystal B is that the o light of λ, the principal refractive index of e light are respectively n _o ⁺, $n_e^{+}(n_e^{+}>n_o^{+}>1).$

Because identical among the situation of prism A and the embodiment 1, so its optimum condition is constant.But, 2} positive crystal B preferably meets the following conditions:

(1) faceted pebble (ef):

[10]，

N wherein ₀The refractive index of expression air;

(2) angle of prism B:

$\sin \mathrm{\ψ}>\frac{n_0}{n_e^{+}},$

[11]，

N wherein ₀The refractive index of expression air;

In addition, between prism A and the prism B required satisfied condition and about the description of compensator C also with embodiment 1 in identical.

(modification 2)

Structure and the principle of the modification of embodiment 2 and embodiment 2 are basic identical, and difference is that the optical axis direction of positive crystal B in this modification is parallel to face efg (being paper).

Therefore, the formula in the foregoing description [10] becomes:

[12]，

N wherein ₀The refractive index of expression air;

Formula [11] becomes:

$\sin \mathrm{\ψ}>\frac{n_0}{n_o^{+}},$

[13]，

N wherein ₀The refractive index of expression air.

In addition, between prism A and the prism B required satisfied condition and about the description of compensator C also with embodiment 1 in identical.

(embodiment 3)

With reference to figure 1, the prism A of present embodiment is made of negative crystal, and prism B is made of isotropic material.Wherein the optical axis direction of prism A is perpendicular to the plane of incidence (being paper) of incident light.The geometric configuration of embodiment 3 is identical with embodiment's 1, repeats no more.

If the unpolarized monochromatic wavelength of incident is λ, negative crystal A is that the o light of λ, the principal refractive index of e light are respectively n to wavelength _o ^-, $n_e^{-}(n_o^{-}>n_e^{-}>1),$ The wavelength of prism B is that the refractive index of λ light is n.

Because identical among the situation of prism A and the embodiment 1, so its optimum condition is constant.But,

2} prism B preferably meets the following conditions:

(1) faceted pebble (ef):

[14]，

N wherein ₀The refractive index of expression air;

(2) angle of prism B:

$\sin \mathrm{\ψ}>\frac{n_0}{n},$

[15]，

N wherein ₀The refractive index of expression air;

In addition, between prism A and the prism B required satisfied condition and about the description of compensator C also with embodiment 1 in identical.

(embodiment 4)

With reference to figure 1, the two prism A and the B of present embodiment constitute by positive crystal.Wherein the optical axis direction of positive crystal A is perpendicular to the plane of incidence (being paper) of incident light, and the optical axis direction of positive crystal B is perpendicular to the plane of incidence (being paper) of incident light.The positive crystal material that constitutes prism B can be different with the positive crystal material that constitutes prism A.The geometric configuration of embodiment 4 is identical with embodiment's 1, repeats no more.

If the unpolarized monochromatic wavelength of incident is λ, the wavelength of positive crystal A is that the o light of λ, the principal refractive index of e light are respectively n _o ⁺, $n_e^{+}(n_e^{+}>n_o^{+}>1),$ The wavelength of positive crystal B is that the o light of λ, the principal refractive index of e light are respectively n _o' ⁺, $n_e^{\′+}(n_e^{\′+}>n_o^{\′+}>1).$

In the present embodiment,

1} positive crystal A preferably meets the following conditions:

(1) faceted pebble (ab):

[16]，

N wherein ₀The refractive index of expression air;

(2) angle of prism A:

 ₀＝ ₁＝θ′+， ₀′＝θ′+′，

[17]，

N wherein ₀The refractive index of expression air;

(3) faceted pebble (cd):

[18]，

N wherein ₀The refractive index of expression air; 2} positive crystal B preferably meets the following conditions:

(1) faceted pebble (ef):

[19]，

N wherein ₀The refractive index of expression air;

(2) angle of prism B:

$\sin \mathrm{\ψ}>\frac{n_0}{n_o^{\′+}},$

[20]，

N wherein ₀The refractive index of expression air;

When satisfying above condition, preferably meet the following conditions between prism A and the prism B:

$H=\frac{\stackrel{\‾}{\mathrm{mn}}}{2N}\cot \mathrm{\θ},$ N＝1，2，…… [21]，

The distance between the faceted pebble (ef) of the faceted pebble (cd) of H ' expression positive crystal A and positive crystal B wherein, H represents the seamed edge of positive crystal A

With seamed edge

Between distance.When H ', H meet above-mentioned condition simultaneously, will guarantee that two light path symmetries in the prism make two parts light can overlap at last synthesising position.

Unpolarized monochromatic light is divided into two bundles at the faceted pebble (ad) of prism A, two-beam is synthetic by the faceted pebble (bc) at prism A after the propagation of two prisms respectively, and synthesize only and form, but exist fixing phase differential between this two bunch polarized light by the orthogonal linearly polarized light in two bundle polarization directions.In order to make the only linearly polarized light of output, need be adjusted into according to the phase differential between two parts linearly polarized light after making synthetic light will synthesize shown in the figure by compensator C (being the Soleil compensator)

Φ＝iπ，i＝0，±1，±2…… [22]，

(modification 4)

Structure and the principle of the modification of embodiment 4 and embodiment 4 are basic identical, and difference is the optical axis direction parallel with the face efg of prism B (promptly being parallel to paper) of positive crystal B in this modification and perpendicular to the faceted pebble (ef) of prism B.

Therefore, in the foregoing description:

2} positive crystal B preferably meets the following conditions:

(1) faceted pebble (ef):

[23]，

N wherein ₀The refractive index of expression air;

(2) angle of prism B:

$\sin \mathrm{\ψ}>\frac{n_0}{n^{\′}},$

[24]，

In addition, between prism A and the prism B required satisfied condition and about the description of compensator C also with embodiment 1 in identical.

(embodiment 5)

With reference to figure 1, the prism A of present embodiment is made of positive crystal, and prism B is made of negative crystal.Wherein the optical axis direction of prism A is perpendicular to the plane of incidence (being paper) of incident light, and the optical axis direction of prism B is perpendicular to the plane of incidence (being paper) of incident light.The geometric configuration of embodiment 5 is identical with embodiment's 4, repeats no more.

If the unpolarized monochromatic wavelength of incident is λ, the wavelength of positive crystal A is that the o light of λ, the principal refractive index of e light are respectively n _o ⁺, $n_e^{+}(n_e^{+}>n_o^{+}>1),$ The wavelength of negative crystal B is that the o light of λ, the principal refractive index of e light are respectively n _o ^-, $n_e^{-}(n_o^{-}>n_e^{-}>1).$

Because identical among the situation of prism A and the embodiment 4, so its optimum condition is constant.But,

2} negative crystal B preferably meets the following conditions:

(1) faceted pebble (ef):

[25]，

N wherein ₀The refractive index of expression air;

(2) angle of prism B:

$\sin \mathrm{\ψ}>\frac{n_0}{n_o^{-}},$

[26]，

N wherein ₀The refractive index of expression air;

In addition, between prism A and the prism B required satisfied condition and about the description of compensator C also with embodiment 4 in identical.

(modification 5)

Structure and the principle of the modification of embodiment 5 and embodiment 5 are basic identical, and difference is the optical axis direction parallel with the face efg of prism B (promptly being parallel to paper) of negative crystal B in this modification and perpendicular to the faceted pebble (ef) of prism B.

Therefore, in the foregoing description:

2} negative crystal B preferably meets the following conditions:

(1) faceted pebble (ef):

[27]，

N wherein ₀The refractive index of expression air;

(2) angle of prism B:

$n^{\′}\sin \mathrm{\ψ}=n_e^{-}\sin (\frac{\mathrm{\π}}{2}-\mathrm{\β}),$ $\sin \mathrm{\ψ}>\frac{n_0}{n^{\′}},$

[28]，

N wherein ₀The refractive index of expression air;

(embodiment 6)

With reference to figure 1, the prism A of present embodiment is made of positive crystal, and prism B is made of isotropic material.Wherein the optical axis direction of prism A is perpendicular to the plane of incidence (being paper) of incident light.The geometric configuration of embodiment 6 is identical with embodiment's 4, repeats no more.

If the unpolarized monochromatic wavelength of incident is λ, the wavelength of positive crystal A is that the o light of λ, the principal refractive index of e light are respectively n _o ⁺, $n_e^{+}(n_e^{+}>n_o^{+}>1),$ The wavelength of prism B is that the refractive index of the light of λ is n.

Because identical among the situation of prism A and the embodiment 4, so its optimum condition is constant.But,

2} prism B preferably meets the following conditions:

(1) faceted pebble (ef):

[29]，

Wherein, n ₀The refractive index of expression air;

(2) angle of prism B:

$\sin \mathrm{\ψ}>\frac{n_0}{n},$

[30]，

In addition, between prism A and the prism B required satisfied condition and about the description of compensator C also with embodiment 4 in identical.

Fig. 2 shows the situation that the bigger light of the refractive index ratio of the different polarization states of co-wavelength among the crystal A penetrates.Following embodiment 7 to 12 all is that accompanying drawing is described with Fig. 2, and these embodiment belong to the situation that the bigger light of refractive index ratio of the different polarization states of co-wavelength among the crystal A penetrates.

(embodiment 7)

With reference to figure 2, two prisms of present embodiment constitute by negative crystal, and wherein the optical axis direction of prism A is perpendicular to the plane of incidence (being paper) of incident light, and the optical axis direction of prism B is perpendicular to the plane of incidence (being paper) of incident light.The negative crystal material that constitutes prism A can be different with the negative crystal material that constitutes prism B.

If the unpolarized monochromatic wavelength of incident is λ, negative crystal A is that the o light of λ, the principal refractive index of e light are respectively n to wavelength _o ^-, $n_e^{-}(n_o^{-}>n_e^{-}>1),$ Negative crystal B is that the o light of λ, the principal refractive index of e light are respectively n to wavelength _o' ^-, $n_e^{\′-}(n_o^{\′-}>n_e^{\′-}>1).$

1} negative crystal A preferably meets the following conditions:

(1) faceted pebble (ab):

[31]，

N wherein ₀The refractive index of showing air;

(2) angle of prism A:

 ₀＝ ₁＝θ′+， ₀′＝θ′+′，

[32]，

N wherein ₀The refractive index of expression air;

(3) faceted pebble (cd):

[33]，

N wherein ₀The refractive index of expression air;

2} negative crystal B preferably meets the following conditions:

(1) faceted pebble (ef):

[34]，

N wherein ₀The refractive index of expression air;

(2) angle of prism B:

$\sin \mathrm{\ψ}>\frac{n_0}{n_o^{\′-}},$

[35]，

N wherein ₀The refractive index of expression air;

When satisfying above condition, preferably meet the following conditions between prism A and the prism B:

$H=\frac{\stackrel{\‾}{\mathrm{mn}}}{2N}\cot \mathrm{\θ},$ N＝1，2，…… [36]，

The distance between the faceted pebble (ef) of the faceted pebble (cd) of H ' expression negative crystal A and negative crystal B wherein, H represents the seamed edge of negative crystal A

With seamed edge

Between distance.When H ', H meet above-mentioned condition simultaneously, will guarantee that two light path symmetries in the prism make two parts light can overlap at last synthesising position.

Unpolarized monochromatic light is divided into two bundles at the faceted pebble (ad) of prism A, two-beam is synthetic by the faceted pebble (bc) at prism A after the propagation of two prisms respectively, and synthesize only and form, but exist fixing phase differential between this two bunch polarized light by the orthogonal linearly polarized light in two bundle polarization directions.In order to make the only linearly polarized light of output, need be adjusted into according to the phase differential between two parts linearly polarized light after making synthetic light will synthesize shown in the figure by compensator C (being the Soleil compensator)

Φ＝iπ，i＝0，±1，±2…… [37]。

(modification 7)

Structure and the principle of the modification of embodiment 7 and embodiment 7 are basic identical, and difference is the optical axis direction parallel with the face efg of prism B (promptly being parallel to paper) of negative crystal B in this modification and perpendicular to the faceted pebble (ef) of prism B therefore, in this modification:

2} negative crystal B preferably meets the following conditions:

(1) faceted pebble (ef):

[38]，

N wherein ₀The refractive index of expression air;

(2) angle of prism B:

$n^{\′}\sin \mathrm{\ψ}=n_e^{\′-}\sin (\frac{\mathrm{\π}}{2}-\mathrm{\β}),$ $\sin \mathrm{\ψ}>\frac{n_0}{n^{\′}},$

[39]，

N wherein ₀The refractive index of expression air.

(embodiment 8)

With reference to figure 2, the prism A of present embodiment is made of negative crystal, and prism B is made of positive crystal.Wherein the optical axis direction of prism A is perpendicular to the plane of incidence (being paper) of incident light, and the optical axis direction of prism B is perpendicular to paper.The geometric configuration of embodiment 8 is identical with embodiment's 7, repeats no more.

If the unpolarized monochromatic wavelength of incident is λ, negative crystal A is that the o light of λ, the principal refractive index of e light are respectively n to wavelength _o ^-, $n_e^{-}(n_o^{-}>n_e^{-}>1),$ The wavelength of positive crystal B is that the o light of λ, the principal refractive index of e light are respectively n _o ⁺, $n_e^{+}(n_e^{+}>n_o^{+}>1).$

Because identical among the situation of prism A and the embodiment 7, so its optimum condition is constant.But,

2} positive crystal B preferably meets the following conditions:

(1) faceted pebble (ef):

[40]，

N wherein ₀The refractive index of expression air;

(2) angle of prism B:

$\sin \mathrm{\ψ}>\frac{n_0}{n_o^{+}},$

[41]，

N wherein ₀The refractive index of expression air;

In addition, between prism A and the prism B required satisfied condition and about the description of compensator C also with embodiment 7 in identical.

(modification 8)

Structure and the principle of the modification of embodiment 8 and embodiment 8 are basic identical, and difference is the optical axis direction parallel with the face efg of prism B (promptly being parallel to paper) of positive crystal B in this modification and perpendicular to the faceted pebble (ef) of prism B.

Therefore, in this modification,

2} positive crystal B preferably meets the following conditions:

(1) faceted pebble (ef):

[42]，

N wherein ₀The refractive index of expression air;

(2) angle of prism B:

$n^{\′}\sin \mathrm{\ψ}=n_e^{-}\sin (\frac{\mathrm{\π}}{2}-\mathrm{\β}),$ $\sin \mathrm{\ψ}>\frac{n_0}{n^{\′}},$

[43]，

N wherein ₀The refractive index of expression air.

(embodiment 9)

With reference to figure 2, the prism A of present embodiment is made of negative crystal, and prism B is made of isotropic material.Wherein the optical axis direction of prism A is perpendicular to the plane of incidence (being paper) of incident light.The geometric configuration of embodiment 9 is identical with embodiment's 7, repeats no more.

If the unpolarized monochromatic wavelength of incident is λ, negative crystal A is that the o light of λ, the principal refractive index of e light are respectively n to wavelength _o ^-, $n_e^{-}(n_o^{-}>n_e^{-}>1),$ The wavelength of prism B is that the refractive index of the light of λ is n.

Because identical among the situation of prism A and the embodiment 7, so its optimum condition is constant.But,

2} prism B preferably meets the following conditions:

(1) faceted pebble (ef):

[44]，

N wherein ₀The refractive index of expression air;

(2) angle of prism B:

$\sin \mathrm{\ψ}>\frac{n_0}{n},$

[45]，

N wherein ₀The refractive index of expression air;

In addition, between prism A and the prism B required satisfied condition and about the description of compensator C also with embodiment 7 in identical.

(embodiment 10)

With reference to figure 2, the two prism A and the B of present embodiment constitute by positive crystal.Wherein the optical axis direction of positive crystal A is perpendicular to the plane of incidence (being paper) of incident light, and the optical axis direction of positive crystal B is perpendicular to the plane of incidence (being paper) of incident light.The positive crystal material that constitutes prism B can be different with the positive crystal material that constitutes prism A.The geometric configuration of embodiment 10 is identical with embodiment's 7, repeats no more.

If the unpolarized monochromatic wavelength of incident is λ, the wavelength of positive crystal A is that the o light of λ, the principal refractive index of e light are respectively n _o ⁺, $n_e^{+}(n_e^{+}>n_o^{+}>1),$ The wavelength of positive crystal B is that the o light of λ, the principal refractive index of e light are respectively n _o' ⁺, $n_e^{\′+}(n_e^{\′+}>n_o^{\′+}>1).$

In the present embodiment,

1} positive crystal A preferably meets the following conditions:

(1) faceted pebble (ab):

[46]，

N wherein ₀The refractive index of expression air;

(2) angle of prism A:

 ₀＝ ₁＝θ′+， ₀′＝θ′+′，

[47]，

N wherein ₀The refractive index of expression air;

(3) faceted pebble (cd):

[48]，

N wherein ₀The refractive index of expression air;

2} positive crystal B preferably meets the following conditions:

(1) faceted pebble (ef):

[49]，

N wherein ₀The refractive index of expression air;

(2) angle of prism B:

$\sin \mathrm{\ψ}>\frac{n_0}{n_e^{\′+}},$

[50]，

N wherein ₀The refractive index of expression air;

When satisfying above condition, preferably meet the following conditions between prism A and the prism B:

$H=\frac{\stackrel{\‾}{\mathrm{mn}}}{2N}\cot \mathrm{\θ},$ N＝1，2，…… [51]，

The distance between the faceted pebble (ef) of the faceted pebble (cd) of H ' expression positive crystal A and positive crystal B wherein, H represents the seamed edge of positive crystal A

With seamed edge

Between distance.When H ', H meet above-mentioned condition simultaneously, will guarantee that two light path symmetries in the prism make two parts light can overlap at last synthesising position.

Unpolarized monochromatic light is divided into two bundles at the faceted pebble (ad) of prism A, two-beam is synthetic by the faceted pebble (bc) at prism A after the propagation of two prisms respectively, and synthesize only and form, but exist fixing phase differential between this two bunch polarized light by the orthogonal linearly polarized light in two bundle polarization directions.In order to make the only linearly polarized light of output, need be adjusted into according to the phase differential between two parts linearly polarized light after making synthetic light will synthesize shown in the figure by compensator C (being the Soleil compensator)

Φ＝iπ，i＝0，±1，±2…… [52]。

(modification 10)

Structure and the principle of the modification of embodiment 10 and embodiment 10 are basic identical, and difference is that the optical axis direction of positive crystal B in this modification is parallel to the face efg of prism B (being paper).

Therefore, in this modification:

2} positive crystal B preferably meets the following conditions:

(1) faceted pebble (ef):

[53]，

N wherein ₀The refractive index of expression air;

(2) angle of prism B:

$\sin \mathrm{\ψ}>\frac{n_0}{n_o^{\′+}},$

[54]，

N wherein ₀The refractive index of expression air;

In addition, between prism A and the prism B required satisfied condition and about the description of compensator C also with embodiment 7 in identical.

(embodiment 11)

With reference to figure 2, the prism A of present embodiment is made of positive crystal, and prism B is made of negative crystal.Wherein the optical axis direction of prism A is perpendicular to the plane of incidence (being paper) of incident light, and the optical axis direction of prism B is perpendicular to the plane of incidence (being paper) of incident light.The geometric configuration of embodiment 11 is identical with embodiment's 10, repeats no more.

If the unpolarized monochromatic wavelength of incident is λ, the wavelength of positive crystal A is that the o light of λ, the principal refractive index of e light are respectively n _o ⁺, $n_e^{+}(n_e^{+}>n_o^{+}>1),$ The wavelength of negative crystal B is that the o light of λ, the principal refractive index of e light are respectively n _o ^-, $n_e^{-}(n_o^{-}>n_e^{-}>1).$

Because identical among the situation of prism A and the embodiment 10, so its optimum condition is constant.But,

2} negative crystal B preferably meets the following conditions:

(1) faceted pebble (ef):

[55]，

N wherein ₀The refractive index of expression air;

(2) angle of prism B:

$\sin \mathrm{\ψ}>\frac{n_0}{n_e^{-}},$

[56]，

N wherein ₀The refractive index of expression air:

In addition, between prism A and the prism B required satisfied condition and about the description of compensator C also with embodiment 10 in identical.

(modification 11)

Structure and the principle of the modification of embodiment 11 and embodiment 11 are basic identical, and difference is that the optical axis direction of negative crystal B in this modification is parallel to the face efg of prism B (being paper).

Therefore, in this modification:

2} negative crystal B preferably meets the following conditions:

(1) faceted pebble (ef):

[57]，

N wherein ₀The refractive index of expression air;

(2) angle of prism B:

$\sin \mathrm{\ψ}>\frac{n_0}{n_o^{-}},$

[58]，

N wherein ₀The refractive index of expression air;

In addition, between prism A and the prism B required satisfied condition and about the description of compensator C also with embodiment 7 in identical.

(embodiment 12)

With reference to figure 2, the prism A of present embodiment is made of positive crystal, and prism B is made of isotropic material.Wherein the optical axis direction of prism A is perpendicular to the plane of incidence (being paper) of incident light.The geometric configuration of embodiment 6 is identical with embodiment's 4, repeats no more.

If the unpolarized monochromatic wavelength of incident is λ, the wavelength of positive crystal A is that the o light of λ, the principal refractive index of e light are respectively n _o ⁺, $n_e^{+}(n_e^{+}>n_o^{+}>1),$ The wavelength of prism B is that the refractive index of the light of λ is n.

Because identical among the situation of prism A and the embodiment 10, so its optimum condition is constant.But,

2} prism B preferably meets the following conditions:

(1) faceted pebble (ef):

[59]，

N wherein ₀The refractive index of expression air;

(2) angle of prism B:

$\sin \mathrm{\ψ}>\frac{n_0}{n},$

[60]，

N wherein ₀The refractive index of expression air;

In addition, between prism A and the prism B required satisfied condition and about the description of compensator C also with embodiment 10 in identical.

In embodiment described above, prism A and prism B are separated from each other, and are fine but utilize principle of the present utility model that prism A and B are connected airtight too.Be example only with the foregoing description 1.As shown in Figure 3, the faceted pebble (cd) that the prism A in the foregoing description 1 is relative with prism B and (ef) connect airtight after, other conditions remain unchanged, and change equation [2] into equation [61]

 ₀＝ ₁＝θ′+， ₀′＝θ′+′，

[61]，

Equation [3] changes equation [62] into

[62]。

In addition, as shown in Figure 3, prism B has a faceted pebble (fs), i.e. xsect and the non-right-isosceles triangle of prism B among Fig. 3.As shown in the figure, adjust properly, the concrete shape of prism B is not had special requirement as long as be used for the faceted pebble (eg), (gs) of total reflection.This point is equally applicable to prism A.

As known in the art, can set up anti-reflection film at device surface place to reduce the reflection loss on transmission surface by light.For example, in the utility model, can locate to adhere to suitable anti-reflection film at the light incident surface of prism A and the light incident surface of Soleil compensator etc., with further reduction intensity loss.

Those skilled in the art can be obvious, can carry out various modifications and variations and not depart from spirit and scope of the present utility model above-mentioned exemplary embodiment of the present utility model.Therefore, be intended to make the utility model to cover to drop in appended claims and the equivalence techniques scheme scope thereof to modification of the present utility model and modification.

Claims (9)

1. a polarization converter is characterized in that, comprises first prism and second prism, and described first prism comprises a plane of incidence, first reflecting surface, second reflecting surface and exit facet, and described second prism comprises plane of refraction, first reflecting surface and second reflecting surface;

The plane of refraction of first reflecting surface of described first prism, second reflecting surface of described first prism and described second prism is parallel to each other;

The plane of incidence in described first prism equates with the angle of first reflecting surface with the exit facet in described first prism with the angle of first reflecting surface, this angle makes the part of incident light reflect at the first reflecting surface place of described first prism, another part generation total reflection, and the feasible light that incides the plane of refraction of described second prism is refracted into described second prism at described plane of refraction place;

Two reflectings surface in described second prism equate with the angle of its plane of refraction, and this angle makes first reflecting surface of described second prism make the light of incident on it along the direction reflection parallel with the plane of refraction of second prism;

Described first prism is made of positive crystal or negative crystal;

Described second prism is made of in positive crystal, negative crystal and the isotropic material any.

2. polarization converter as claimed in claim 1, it is characterized in that, the angle of the plane of incidence of described first prism and first reflecting surface is set to: make to enter described first prism with the luminous energy of being scheduled to incident angle incident, in described first prism, reflect into two-beam, and total reflection takes place at the described first reflecting surface place in wherein a branch of light then, another Shu Guang reflects at the described first reflecting surface place, and the feasible light that incides the plane of refraction of described second prism is refracted into described second prism at described plane of refraction place.

3. polarization converter as claimed in claim 1, it is characterized in that, the reflecting surface of described second prism and the angle of its plane of refraction are set to: make the light that is refracted into described second prism at the first reflecting surface place of described second prism total reflection take place, and make through the direction propagation parallel with the plane of refraction of described second prism of the light edge of described total reflection.

4. polarization converter as claimed in claim 1 is characterized in that, first reflecting surface of described first prism and the plane of refraction of described second prism connect airtight.

5. polarization converter as claimed in claim 1 is characterized in that, first reflecting surface of described first prism separates with the plane of refraction of described second prism.

6. polarization converter as claimed in claim 1 is characterized in that, also comprises the compensator of the exit facet place setting of described first prism.

7. polarization converter as claimed in claim 1 is characterized in that, the surface of passing through light of each optical device in described polarization converter is the plating anti-reflection film all.

8. polarization converter as claimed in claim 1, it is characterized in that first reflecting surface of described first prism is set to distance between second reflecting surface: thus the described two parts luminous energy that separates of light path symmetry in first prism is overlapped at the exit facet place of described first prism.

9. polarization converter as claimed in claim 1, it is characterized in that first reflecting surface of described first prism is set to distance between the plane of refraction of described second prism: thus the described two parts luminous energy that separates of light path symmetry in second prism is overlapped at the exit facet place of described first prism.

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