WO2019007175A1

WO2019007175A1 - Efficient optical path folding device

Info

Publication number: WO2019007175A1
Application number: PCT/CN2018/089621
Authority: WO
Inventors: 陈波; 许辉杰; 温俊华; 陈从干
Original assignee: 徐州旭海光电科技有限公司
Priority date: 2017-07-04
Filing date: 2018-06-01
Publication date: 2019-01-10
Also published as: CN109477953B; CN109212733B; CN109212733A; CN109477953A

Abstract

According to an efficient optical path folding device provided in this solution, an inclined sub-reflector is introduced to an optical reflection cavity focal plane, and the circulation condition of reflected light is damaged, so that the light is reflected in a reflection cavity multiple times so as to implement a long optical path; moreover, a second inclined sub-reflector and a strip-shaped reflector are introduced so as to implement two-dimensional arrangement of light spots, thereby achieving more reflections and a longer optional path; the size and divergent features of the light spots when the light is input are maintained when the light is output, and therefore, the input conditions of coherent light and incoherent light are met; furthermore, a controller is introduced, the inclined sub-reflector is driven to rotate, the range of the inclined sub-reflector is changed, so as to the number of reflections of the light in the reflection cavity, thereby achieving the variable characteristics of the optical path. According to this solution, light beam input and output of an array are further allowed, so as to achieve the purpose of detecting various gases simultaneously, or to implement series connection, thereby achieving a long optical path.

Description

Efficient optical path folding device

Technical field

The solution relates to an optical path folding device in the field of optical sensing, and more particularly to an efficient optical path folding device for gas optical sensing and variable optical path.

Background technique

In a limited volume, multiple reflections of the beam are achieved, and the beam travels through a relatively long optical path. Such optics have important applications in the field of optical sensing, particularly in the field of sensing and analysis of specialty gases.

At present, semiconductor tunable laser absorption spectroscopy (hereinafter referred to as TDLAS) and Fourier transform infrared spectroscopy (hereinafter referred to as FTIR) are two mainstream technical routes. The former is mainly based on tunable laser in the near-infrared band for spectral analysis, the latter. Spectral analysis was performed in the far-infrared region by Fourier transform using a broad-spectrum light source.

In order to achieve sufficient detection accuracy, both TDLAS and FTIR require a long path cavity to allow the beam to transmit enough optical path within the desired analytical gas to enhance the absorption line, in order to make the volume of the detector instrument acceptable. In the range, the long path cavity needs to be in the form of an optical path folding device to reflect the beam as many times as possible within a finite volume to achieve a sufficient optical path.

For TDLAS applications, the Herriot chamber structure (APPLIED) is widely used in the industry due to the small divergence angle of the laser beam. OPTICS / Vol. 3, No. 4 / April 1964), as shown in Figure 1, the Herriot chamber (100) uses two concave mirrors (103, 104) with the same focal length f to form a reflective cavity when input When the incident direction and position of the input beam of the end (101) and the distance d of the two concave mirrors in the z direction satisfy a certain condition (generally, a defocusing configuration of 0<d<2f or 2f<d<4f), the beam will be The two concave mirrors are reflected back and forth multiple times and finally output from the output (102). On the two concave mirrors (203, 204) shown in the table of Figure 2, the reflection points form a circular spot trajectory (201) on the x-y plane.

For FTIR applications, since the light source requires an incoherent broad-spectrum thermal source, the beam divergence angle is large and the performance of the Herriot chamber is not satisfactory, due to the defocusing configuration characteristics necessary for the Herriot chamber, the defocusing system The incoherent beam divergence angle cannot converge after multiple reflections, and the traditional white chamber structure is commonly used in the industry (White, JU "Long Optical" Paths of Large Aperture" J. Opt. Soc. Am., Vol. 32, pp 285-288, May 1942), as shown in FIG. 3, the White Room (300) is composed of three concave mirrors having the same radius of curvature and focal length f, the primary mirror (301) is located on one side, and the secondary mirrors (302, 303) Located on the opposite side of the main mirror, the input beam (304) and the output beam (305) are located on either side of the main mirror. The two secondary mirrors have a certain inclination angle, and the distance between the primary mirror and the two secondary mirrors is set to 2f, so that the light beam is reflected and reflected multiple times in the primary mirror and the two secondary mirrors, and finally from the side of the primary mirror. Output. The trajectory of the spot on the primary mirror is shown in Figure 4. Typically, the input beam position (404) is offset from the main mirror (401) axis (402) such that the spot is distributed over the two rows of tracks (403, 406) to Get the maximum number of reflections. The output beam position (405) is typically on the other side of the same row of tracks (406) as the input beam.

As the industry's requirements for gas detection accuracy increase, the requirements for the optical path chamber are further improved, and a longer optical path (more than 20 meters, or even more than 100 meters) is required in a limited volume. The Herriot chamber It is difficult for the White Room to achieve more reflections within a certain volume. There are many improved designs based on the Herriot and White rooms, such as Herriot's own astigmatic lens for more reflections ("Folded Optical Delay Lines", Appl. Opt., Vol. 4, No. 8, pp 883-889, 1965), but there is a problem that astigmatic lenses are difficult to process, although there is a need to reduce the processing accuracy by rotating an astigmatic lens (US Patent 5,291,365, 1994). There is still no solution to the high processing cost of astigmatic lenses; Joel.A.Silver et al. propose a dense cylindrical spot distribution with more cylindrical reflections (ie, US Patent 7477377, 2009), but due to the double cylinder The non-rotational symmetry property, the beam no longer has the same beam characteristics as the input beam after multiple reflections, and cannot be applied in applications where beam characteristics (beam radius, divergence half angle, etc.) are required. Although there are some improvements based on the White Room, such as the Chinese patent "Folding Double-Optical Multi-Pass Gas Pool" (CN102053063B) uses a corner mirror at the output of the White Room to reflect the output beam back along the original path (off one Small angle), the optical path is doubled, but the input and output are too close, requiring more space to separate the input and output beams. At the same time, the White room uses an angled secondary mirror. After multiple reflections of the beam, the aberration is output. The influence of the beam characteristics is large.

technical problem

The existing long-path gas chamber has a large volume, an optical path volume ratio is not high, the optical path is difficult to further expand, the optical path is difficult to change, and the astigmatic lens processing is difficult, and the beam characteristics (beam radius, divergence half angle, etc.) are required. There are many problems that cannot be applied in the application scenario that is maintained.

Technical solution

The first aspect of the embodiment of the present invention provides an efficient optical path folding device, comprising:

An input for inputting a light beam;

An output for outputting a light beam, the input end being disposed separately from the output end;

a main plane mirror;

a concave mirror having a focal plane, the focal plane to the concave mirror being a focal length f of the concave mirror; the focal plane having an origin, the origin being the principal plane mirror An intersection of an optical system optical axis composed of a concave mirror on the focal plane;

a first tilting sub-reflector having a smaller area than the plane mirror of the main plane mirror, an inclination angle between a normal line of the first inclined sub-mirror and a normal line of the main plane mirror is θ1 The tilt angle θ1 is not zero;

An entrance surface of the input end, an exit surface of the output end, the main plane mirror and the first tilt sub-mirror are coplanar and located at a focal plane of the concave mirror;

A light beam is input from the input end, and is output from the output end through multiple reflections between the concave mirror, the main plane mirror, and the first tilt sub-mirror.

In one embodiment, the high efficiency optical path folding device further includes:

a second tilting sub-reflector having a smaller area than the plane mirror of the main plane mirror, and an inclination angle between a normal line of the second inclined sub-mirror and a normal line of the main plane mirror is θ2 a projection of the inclination angle θ2 and the inclination angle θ1 on the focal plane is not parallel;

a first mirror, which is a plane mirror having an area smaller than the main plane mirror, an inclination angle between a normal line of the first mirror and a light beam incident thereon is γ1; the inclination angle γ1 Not zero;

An entrance surface of the input end, an exit surface of the output end, the main plane mirror, the first tilt sub-mirror, the second tilt sub-mirror and the first mirror are coplanar and located a focal plane of the concave mirror, the input end and the output end are located at the same end of the main plane mirror, and the first mirror is disposed opposite to the input end and the output end The other end of the main plane mirror;

a light beam is input from the input end through the concave mirror, the main plane mirror, the first tilt sub-mirror, the second tilt sub-mirror, and the first mirror After multiple reflections, output from the output.

a second mirror, which is a plane mirror having an area smaller than the main plane mirror, an inclination angle between a normal line of the second mirror and a light beam incident thereon is γ2; the inclination angle γ2 Not zero;

An incident surface of the input end, an exit surface of the output end, the main plane mirror, the first tilt sub-mirror, the second tilt sub-mirror, the first mirror, and the first Two mirrors are coplanar and located in a focal plane of the concave mirror, and the input end, the output end and the second mirror are located at the same end of the main plane mirror, or a mirror and the output end are located at the same end of the main plane mirror;

a light beam is input from the input end through the concave mirror, the main plane mirror, the first tilt sub-mirror, the second tilt sub-mirror, the first mirror, and the After multiple reflections between the second mirrors, they are output from the output.

In one embodiment, the input beam has a radius of A0 and a divergence half angle of β0;

The distance of the first tilt sub-mirror from the origin of the focal plane is greater than the product of the divergence half angle of the input beam and the focal length of the concave mirror β0·f.

In one embodiment, the first tilting sub-mirror is located at a position where the input beam reaches the focal plane after being reflected by the concave mirror for the first time or the third time, the first tilting sub-mirror The pass light diameter is greater than 2β0·f.

In one embodiment, the direction of the oblique angle of the first tilting sub-mirror is such that when the input beam passes through the even-numbered reflections of the concave mirror and reaches the focal plane, the center of the input beam is The distance of the first inclined sub-mirror boundary is greater than the radius A0 of the input beam.

In one embodiment, the input end is a first fiber collimator with a first pigtail, and a light beam is input through the first fiber collimator;

Or the input end is a first fiber collimator array with a first pigtail array, and a light beam is input through the first fiber collimator array;

Or the input end is a light passing hole or an opening angle on the main plane mirror, and the light beam enters the input end from the free space;

Alternatively, the input end is connected to the light emitting device through an optical fiber, and the input end inputs a light beam emitted by the light emitting device;

The output end is a second fiber collimator with a second pigtail, and the output beam is output through the second fiber collimator;

Or the output end is a second fiber collimator array with a second pigtail array, and the output beam is output through the second fiber collimator array;

Or the output end is a light passing hole or an opening angle on the main plane mirror, and the output light beam is output from the output end to a free space;

Or the output end is connected to the photodetector through an optical fiber, and the output beam is received by the photodetector;

Alternatively, the output is coupled to the array of photodetectors via an optical fiber, and the output beam is received by the array of photodetectors.

a driver for driving the first tilting sub-mirror to rotate in an oblique direction thereof to change the magnitude of the tilting angle θ1 such that a total optical path of the light beam from the input end to the output end is variable;

An angle measuring device for measuring the tilt angle θ1;

Wherein the driver is one of a piezoelectric ceramic type or an electromagnetic type driver, and the angle measuring device is an optical angle measuring device with a measuring laser and a four-quadrant detector.

a driver for driving the first tilting submirror and the second tilting submirror to rotate in respective tilting angle directions to change the tilting angle θ1 and the tilting angle θ2 to thereby make the light beam The total optical path from the input to the output is variable;

An angle measuring device for measuring the tilt angle θ1 and the tilt angle θ2;

In one embodiment, the output is located at a position of the focal plane after the input beam is reflected by the concave mirror 4 by a positive integer multiple.

A second aspect of the embodiment of the present invention provides an efficient optical path folding device, comprising:

An input and output terminal for the input beam and the output beam;

a main plane mirror;

a first mirror, which is a planar mirror having a smaller area than the main plane mirror, a normal of the first mirror being parallel to a beam incident thereon or a normal of the first mirror The inclination angle between the light beams incident thereon is γ1; the inclination angle γ1 is not zero;

The incident exit surface of the input and output ends, the main plane mirror, the first tilt submirror and the first mirror are coplanar and located at a focal plane of the concave mirror, the first strip a mirror is disposed at the other end of the main plane mirror with respect to the input and output end;

a light beam is input from the input and output end, and after the multiple reflection between the concave mirror, the main plane mirror, the first inclined sub-mirror, and the first mirror, Input/output output, when the normal of the first mirror is parallel to the light beam incident thereon, the angle of the light beam incident and outgoing from the input and output ends is 0 and the direction is opposite; the first reflection When the inclination angle between the normal line of the mirror and the light beam incident thereon is γ1, the angle of the light beam incident and outgoing from the input and output ends is 2γ1.

a second tilting sub-reflector having a smaller area than the plane mirror of the main plane mirror, and an inclination angle between a normal line of the second inclined sub-mirror and a normal line of the main plane mirror is θ2 The projections of the tilt angles θ2 and θ1 on the focal plane are not parallel;

a third mirror, which is a planar mirror having an area smaller than the main plane mirror, a normal of the third mirror being parallel to a beam incident thereon or a normal of the third mirror The inclination angle between the light beams incident thereon is γ3; the inclination angle γ3 is not zero;

An incident exit surface of the input and output ends, the main plane mirror, the first tilt sub-mirror, the second tilt sub-mirror, the first mirror, the second mirror, and The third mirror is coplanar and located at a focal plane of the concave mirror, and the input and output ends, the second mirror and the third mirror are located in the same plane mirror end;

a light beam is input from the input and output end, through the concave mirror, the main plane mirror, the first tilt sub-mirror, the second tilt sub-mirror, the first mirror, the After multiple reflections between the second mirror and the third mirror, output from the input and output ends, when the normal of the third mirror is parallel to the light beam incident thereon, The angle between the incident and outgoing beams is 0 and the direction is opposite; when the inclination angle between the normal of the third mirror and the beam incident thereon is γ3, from the input and output ends The angle between the incident and outgoing beams is 2 γ3.

In one embodiment, the input and output ends are fiber-optic collimators with pigtails through which light beams are input and output;

Or the input and output ends are an array of fiber collimators with a pigtail array, and the light beam is input and output through the fiber collimator array;

Or the input and output ends are light passing holes or opening angles on the main plane mirror, and the light beam enters the input and output ends from the free space;

Alternatively, the input and output end is connected to the light emitting device and the photodetector through an optical fiber, and the input and output end inputs a light beam emitted by the light emitting device, and the output light beam is received by the photodetector;

Alternatively, the input and output terminals are connected to the photodetector array through an optical fiber, and the output beam is received by the photodetector array.

An angle measuring device for measuring the tilt angle θ1;

Beneficial effect

The high-efficiency optical path folding device provided by the embodiment of the present invention can achieve more reflection times, that is, longer optical path, and higher light, compared with the Herriot chamber and the white room after the introduction of the first tilting mirror. Through the introduction of the second tilting mirror and the strip mirror, the reflected light spot realizes two-dimensional arrangement, further increasing the optical path and optical path volume ratio; the output beam maintains the same beam characteristics as the input beam (beam radius and divergence half angle) Etc.), it can be used for scenes with small beam divergence angles, and for scenes with large beam divergence angles; the optical path variable function is further realized by adjusting the angle of the first or second tilt mirrors by the driver.

DRAWINGS

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly described below. Obviously, the drawings in the following description are some embodiments of the present solution, Those skilled in the art can also obtain other drawings based on these drawings without paying any creative work.

Figure 1 is a schematic diagram of a prior art Herriot chamber;

2 is a trajectory diagram of a reflection point spot of a Herriot chamber in the prior art;

Figure 3 is a schematic diagram of a prior art white room;

4 is a trajectory diagram of a beam reflection point spot of a white room in the prior art;

FIG. 5 is a schematic diagram of an efficient optical path folding device according to Embodiment 1 of the present embodiment; FIG.

6a is a distribution of a beam position of a high-efficiency optical path folding device in a focal plane and a position of a tilt sub-mirror according to Embodiment 1 of the present embodiment;

6b is a perspective view showing the tilting direction of the tilt sub-mirror in the high efficiency optical path folding device provided in the first embodiment of the present invention;

7 is a schematic diagram of a variable optical path high efficiency optical path folding device according to Embodiment 1 of the present embodiment;

8 is a schematic diagram of an efficient optical path folding device with an input end of a fiber collimator array provided in Embodiment 1 of the present embodiment;

9 is a schematic diagram of an efficient optical path folding device in which an input and an output end are an optical fiber collimator array and an optical path is connected in series according to Embodiment 1 of the present embodiment;

FIG. 10 is a schematic diagram of an efficient optical path folding device according to Embodiment 1 of the present embodiment; FIG.

11 is a schematic diagram of an efficient optical path folding device according to Embodiment 1 of the present embodiment;

FIG. 12 is a schematic diagram of an efficient optical path folding device according to Embodiment 1 of the present embodiment; FIG.

13a and 13b are schematic diagrams of the high efficiency optical path folding device provided in the second embodiment of the present invention;

14a and 14b are schematic diagrams of the high efficiency optical path folding device provided in the third embodiment of the present invention;

15a and 15b are schematic diagrams of the high efficiency optical path folding device provided in the fourth embodiment of the present invention;

16a and 16b are schematic diagrams of an efficient optical path folding device provided in Embodiment 5 of the present embodiment.

Embodiments of the invention

In order to enable the person skilled in the art to better understand the present solution, the technical solutions in the embodiments of the present solution will be clearly described below with reference to the accompanying drawings in the embodiments of the present embodiments. It is obvious that the described embodiments are part of the present solution. Embodiments, rather than all of the embodiments. Based on the embodiments in the present solution, all other embodiments obtained by those skilled in the art without creative efforts shall fall within the scope of protection of the present solution.

The term "comprising" and variations of the terms in the specification and claims of the present invention and the above-described drawings are intended to cover non-exclusive inclusions. Moreover, the terms "first" and "second" and the like are used to distinguish different objects and are not used to describe a particular order.

Embodiment 1

As shown in FIG. 5, the solution provides an efficient optical path folding device 500, including:

An input end 501 for inputting a light beam;

An output end 502 for outputting a light beam, the input end 501 being disposed separately from the output end 502;

a main plane mirror 504;

A concave mirror 503 having a focal plane 506, the distance 507 from the focal plane 506 to the concave mirror 503 is the focal length f of the concave mirror 503; the focal plane 506 has an origin 509, which is The intersection of the optical plane optical axis 508 of the main plane mirror 504 and the concave mirror 503 on the focal plane 506.

a first tilting sub-mirror 505 is a planar mirror having a smaller area than the main plane mirror 504, between the normal of the first tilting sub-mirror 505 and the normal of the main plane mirror 504 The inclination angle is θ1; the inclination angle θ1 is not zero;

The incident surface of the input end 501, the exit surface of the output end 502, the main plane mirror 504 and the first tilt sub-mirror 505 are coplanar and located in the focal plane 506 of the concave mirror 503;

A light beam is input from the input terminal 501, and is output from the output terminal 502 through multiple reflections between the concave mirror 503, the main plane mirror 504, and the first tilt sub-mirror 505.

From the optical characteristics, since the confocal system is employed, the radius and divergence half angle of the beam will be changed between the two sets of values on the focal plane 506, regardless of the number of reflections of the concave mirror 503, only with the concave mirror 503. The parity of the number of reflections is related. It is assumed that the input beam 501 has a radius of the input beam A0 and a divergence half angle of β0. After the reflection of the concave mirror 503 reaches the focal plane 506, the radius of the beam is A ₁ and the divergence angle is β ₁ , which has the following relationship:

A ₁ = β0·f (1)

β ₁ = A0/ f (2)

After the reflection of the concave mirror 503 reaches the focal plane 506, the radius of the beam is A ₂ and the divergence half angle is β ₂ , which can be obtained by applying (1) and (2) twice:

A ₂ = β ₁ · f = (A0/ f)·f = A0 (3)

β ₂ = A ₁ / f = (β0·f) / f = β0 (4)

It can be seen from equations (3) and (4) that the input beam is reflected by the two concave mirrors 503 and reaches the focal plane 506, and the characteristics of the input beam are recovered (A0, β0), which is easy to see through the even number of concave mirrors. After the reflection of 503, the characteristics of the beam will be the same as the input beam; for the reflection of the odd-numbered concave mirror 503, the characteristics of the beam will take the radius and divergence half angles (A ₁ , β ₁ ) obtained by (1) and (2). .

For the transformation of the main beam position and angle of the input beam (relative to the optical axis composed of the main plane mirror 504 and the concave mirror 503), in the case where the first tilt sub-mirror 505 is not introduced, it can be proved that after four times of concave surface After the reflection of the mirror 503 reaches the focal plane, the main beam position of the beam coincides with the position of the main beam of the input beam, and the angle of the main beam of the input beam is mirror-symmetrical with respect to the optical axis; since the main beam position of the beam is the main beam of the input beam The beam positions are coincident, the beam is no longer reflected by the main plane mirror 504, and is output through the input terminal 502. Therefore, in the case where the first tilt sub-mirror 505 is not introduced, the beam is reflected by the concave mirror 503 at most four times, the total light. The process is very limited.

The present scheme introduces a first tilting sub-mirror 505 on the confocal optical system composed of the concave mirror 503 and the main plane mirror 504, the position of which is offset from the origin 509 by a certain distance, and is located at the input beam through the concave mirror 503. The position of the secondary or third reflection reaching the focal plane 506, the first tilting sub-mirror 505 changes the angle of reflection of the beam, and after the beam is reflected by the concave mirror 503, the subsequent reflected beam is changed on the focal plane 506. The position of the odd-numbered reflected beams is constant on the focal plane 506 such that the positions of all of the beams no longer collide with the input 501, achieving multiple reflections of the beam.

It can be shown that, as shown in Fig. 6a, after the first inclined sub-mirror 505 is introduced, on the focal plane 506 where the main plane mirror 504 is located, through the concave mirror 1+4n (n = 0, 1, 2, 3) ······· After the secondary reflection, the position of the beam is at the same position, denoted as P ₁ (ie 601); through the concave mirror 3+4n (n=0,1,2,3····· ·) After the secondary reflection, the position of the beam is at the same position, denoted as P ₃ (ie 602); after the concave mirror 4+4n (n=0,1,2,3······) The positions of the beams are P ₄ , P ₈ , P ₁₂ ······, which are in line with the position P _{0 of the} input beam, denoted as L ₄ (ie 603); through the concave mirror 2+4n ( n=0,1,2,3·······) After the secondary reflection, the positions of the beams are P ₂ , P ₆ , P ₁₀ ······, which are on a straight line, denoted as L ₂ ( Ie 604).

For convenience of explanation, in FIGS. 6a and 6b, the first tilting sub-mirror 505 is selected at the position P ₃ (ie 602) of the beam at the focal plane after the third reflection by the concave mirror 503, its normal 605 and The normal line 606 of the principal plane mirror 504 forms an inclination angle θ1, and a ridge line formed by the intersection of the plane formed by the two normal lines and the focal plane 506 is a vector called a shift vector ΔP (ie, 607), the length thereof. Defined by:

ΔP= tan(2θ1)·f (5)

Proved to be easily distributed on the _two beam position _{_{_{P 2, P 6, P 10}}} ······, and distribution of the ₄ position of the beam L _{_{_{P 0, P 4, P 8}}} L, P 12 ······ The adjacent beam position interval is ΔP given by equation (5), and L ₂ and L _{4 are} parallel to ΔP. It can be seen that ΔP contains the magnitude and direction of the tilt angle θ1 of the tilted submirror.

It can be seen from the properties of the confocal optical system that P ₁ (601) and P ₃ (602) are symmetric with respect to the origin 509 of the focal plane, so that the first tilt sub-mirror 505 does not interfere with the light beam on P ₁ , the first tilt The distance of the mirror 505 from the focal plane origin 509 is greater than the beam radius A ₁ on P ₁ or P ₃ , and A ₁ =β0·f is known from the above formula (1); at the same time, to ensure that the first tilt sub-mirror 505 can reach the reflection All beam energies on it have a light passing diameter greater than the beam diameter 2·A ₁ on P ₁ or P ₃ , ie 2β0·f.

In order to avoid the interference of the first tilting sub-mirror 505 on the light beam on L ₂ or L ₄ , the direction of the tilt angle θ1 is selected such that the direction of the shift vector ΔP is not in the direction of the line connecting the input end 501 and P ₃ (602), Forming a certain angle, after the reflection of the even number of concave mirrors 503, the distance from the center of the input beam to the boundary of the first tilting sub-mirror 505 when the beam reaches the focal plane 506 is greater than the radius A0 of the input beam, thereby The pass band having a beam diameter as a width on L ₂ or L ₄ does not overlap with the first tilt sub-mirror 505.

The output 502 can be taken on L ₂ or L ₄ , preferably on L ₄ collinear with the input, ie the output 502 is located at a positive integer multiple of the input beam reflected by the concave mirror 503 4 number reaches position 506 after the focal plane, and therefore both the input terminal 501 and output terminal 502 L ₄ (603); an output terminal 502 of this arrangement that the position and angle of the output beam relative to the concave mirror 503 The angle of the main plane mirror 504 is insensitive to positional deviation and the optical system has high stability.

In specific applications, the form of the aperture and the opening angle is suitable for the case of a non-coherent input beam with a large divergence angle, and the beam is input by free-space propagation; for a coherent beam with a small divergence angle for the input beam, such as a laser, the selection band A pigtail fiber collimator is used as the beam input end, and the output end selects the fiber collimator output beam with the pigtail, and the photodetector can directly receive the beam.

An angle measuring device for measuring the tilt angle θ1;

In many applications, the optical path of the device is required to be variable. For this reason, the solution also provides a high-efficiency optical path folding device with variable optical path, as shown in FIG. 7, in the concave mirror 503 and the main plane. Based on the confocal optical system composed of the mirror 504 and the first tilting sub-mirror 505 and the input end 501 and the output end 502, the first tilting sub-mirror 505 can be rotated in an oblique direction to change its normal line 605 and The normal angle 606 of the main plane mirror 504 forms a tilt angle θ1 whose rotation axis 701 is within the focal plane 506 where the main plane mirror 504 is located and is driven to rotate by a driver 702. The tilt angle θ1 is determined by an angle measuring device. 703 measurement.

The tilt angle θ1 is variable to cause the shift vector ΔP(607) to be variable. As long as the tilt angle θ1 is selected such that the distance between the input end 501 and the output end 502 is an integer multiple of ΔP, the light beam can be reflected to the output end 502 by multiple reflections. In order to achieve the purpose of changing the total optical path.

The driver 702 may be one of a piezoelectric ceramic type or an electromagnetic type driver. The angle measuring device 703 can be an optical angle measuring device with a measuring laser and a four-quadrant detector. The laser reaches the four-quadrant detector after being reflected by the first tilting sub-mirror, and is calculated by comparing the light intensity data of the four-quadrant detector. The magnitude and direction of the tilt angle θ1.

In practical applications, it is sometimes necessary to simultaneously input lasers of multiple spectral segments into a high-efficiency optical path folding device to detect different gas components. In the prior art, a wavelength coupler is used to couple multiple wavelengths of laser light into one pigtail, and then Input through fiber collimator; for this kind of simultaneous laser input requiring multiple spectral segments, the solution also provides an efficient optical path folding device for array input and output, as shown in Figure 8, the array laser beam The first fiber collimator array 801 with the first pigtail array is parallel input, the second fiber collimator array 802 with the second pigtail array is output in parallel, or the photodetector array 802 is used for parallel reception. The plurality of light beams input in parallel by the first fiber collimator array 801 have the same angle with respect to the optical axis, and thus are reflected by the concave mirror 1+4n (n=0, 1, 2, 3······) After that, the position of the beam is the same as P ₁ ; after the concave mirror 3+4n (n=0,1,2,3······), the position of the beam is the same as P ₃ ; the concave mirror After 4+4n (n=0,1,2,3······) secondary reflection, the position distribution of the beam is consistent with the single input in the ΔP(607) direction, but in the first fiber collimator array The alignment direction (803) is unfolded; after the concave mirror 2+4n (n=0,1,2,3······) is reflected, the position of the beam is 4+4n (n=0,1, 2,3······) The positional distribution of the beam formed by the secondary reflection is similar, and is developed in the ΔP direction and the arrangement direction of the first fiber collimator array, and the two sets of beam positions are symmetrically distributed with respect to the origin 509 on the focal plane 506.

In order to achieve a longer optical path, the solution also provides an optical path series device, and the input end shown in FIG. 8 is a first fiber collimator array with a first pigtail array, and the output end is a band. Based on the second fiber collimator array of the two-tail fiber array, as shown in FIG. 9, a part of the pigtails of the first pigtail array 901 and the second pigtail array 902 are connected through an optical fiber, and are connected in series to have only one input tail. The input end of the fiber 903 and the output end of only one output pigtail 904, in this way, the light beam is input from the input pigtail 903, and after repeated reflection and series connection of the pigtail by the high-efficiency optical path folding device, the input is repeatedly input to the high-efficiency light. The device is folded until it is output from the output pigtail 904. If the first pigtail array has M pigtails, the total optical path is M times the optical path of a single device.

Due to the excellent optical properties of the reflective confocal system, the concave mirror can be a cheap and mature spherical mirror in the case of a small beam divergence angle (such as coherent light); the beam divergence angle is relatively large (eg, non-coherent) In the case of light), an aspherical mirror can be used as the concave mirror.

It can be seen from the previous analysis that the high-efficiency optical path folding device provided by the present scheme maintains the same beam characteristics (beam radius and divergence half angle, etc.) as the input beam, and can be used for scenes with small beam divergence angle, and also available. In the scene where the beam divergence angle is large; compared with the Herriot chamber and the White room, due to the reuse of P ₁ and P ₃ , the high efficiency optical path folding device provided by the scheme can achieve more due to the same volume. The number of reflections is a longer optical path, and a higher optical path volume ratio; since the beam characteristics are maintained after the concave mirror is reflected several times, it is easier to expand to a dense beam, so that the number of reflections and the total optical path are further increased; Inclining the angle of the sub-mirror and thus changing the total optical path makes the optical path variable device easier to implement in engineering; the high-efficiency optical path folding device with the optical fiber collimator array as the input end eliminates the wavelength coupler The use can be directly applied to multi-wavelength input to realize real-time detection of multi-gas components; the solution provides the fiber collimator array as input and output. Effective optical path folding means, is connected via fiber optic pigtails, the optical path in series to obtain a greater optical path, for more accurately detecting the gas has significant value.

As shown in FIG. 10, in one embodiment, the light-passing apertures on the main plane mirror 504 of the input end 501 and the output end 502 are exemplarily shown, and the light beams are input and output by free-space propagation.

The input beam is incoherent with a radius of A0 and a divergence half angle of β0. The distance of the first tilting sub-mirror 505 from the origin 509 is taken as 2β0·f, and is located at the position where the input beam is reflected by the concave mirror 503 to the focal plane 506 for the third time, and the tilting direction thereof is input to the input end 501 and the output end 502. The connection direction is parallel, and the aperture is taken as 3β0·f, so that the beam diameter 2β0·f reaching thereon can be covered, and a certain redundant aperture is left; the edge of the first tilt sub-mirror 505 is away from the input end 501 and the output end. The shortest distance of the connection of 502 is 2 times the radius of the input beam, that is, 2A0, so that the aperture of the first tilting sub-mirror 505 does not interfere with other beams.

Since the input beam has a large divergence angle, the concave mirror 503 employs an aspherical mirror to obtain excellent optical performance.

As shown in FIG. 11, in one embodiment, the input 501 and the output 502 are exemplarily shown as fiber-optic collimators with pigtails, the input beam is coherent light, and the input from the fiber collimator to the high-efficiency light The beam of the folded device is a Gaussian beam with a Gaussian beam waist radius ω and a far field divergence half angle α, defining a beam radius of A0=3ω, a divergence half angle β0=3α, to cover most of the energy of the Gaussian beam, and thereby obtaining the first The distance of a tilt sub-mirror 505 from the origin 509 is 6α•f, and the aperture is taken as 9α•f; the shortest distance between the edge of the tilt sub-mirror and the line connecting the input and the output is 6ω.

In a particular application, the concave mirror is one of a spherical mirror or an aspheric mirror.

In one embodiment, the concave mirror 503 is taken as a spherical mirror.

Take ω=0.2mm, f=200mm, α=2.5mrad In this case, it can be obtained that the distance of the first inclined sub-mirror from the origin is about 3 mm, the aperture is about 4.5 mm, and the shortest distance from the edge of the aperture to the line connecting the input and the output is 1.2 mm. In the case of the same adjacent beam distance, the high-efficiency optical path folding device provided by the embodiment has an optical path of more than twice the optical path of the Herriot chamber and the white chamber, and has a higher optical path volume ratio.

As shown in FIG. 12, in one embodiment, the first tilting sub-mirror 505 of the high-efficiency optical path folding device shown in FIG. 10 can be rotated in an oblique direction, that is, the magnitude of the tilt angle θ1 can be changed, and the rotating shaft 701 is in the main The focal plane 506 in which the planar mirror 504 is located is driven by a piezoelectric ceramic type driver 1201 for rotation. The tilt angle θ1 is measured by an optical angle measuring device 1202 having a measuring laser and a four-quadrant detector. The laser reaches the four-quadrant detector after being reflected by the tilting sub-mirror, and the magnitude and direction of the tilt angle θ1 are obtained by comparing the light intensity data of the four-quadrant detector.

The tilt angle θ1 is variable, and the shift vector ΔP is variable. The tilt angle θ is selected such that the distance between the input end and the output end is an integer multiple of ΔP, so that the light beam can be sent from the input end 501 to the output end 502, thereby changing the total optical path. the goal of.

Embodiment 2

As shown in FIGS. 13a and 13b, based on the first embodiment, the present embodiment provides an efficient optical path folding device 600, which adds a first line at the output end 502 to the optical path folder 500. The mirror 1301 removes the output 502, replaces the input 501 with an input and output 1302, and places the first tilted sub-mirror 1301 at the edge of the main plane mirror 504.

In this embodiment, the first mirror 1301 is a plane mirror having a smaller area than the main plane mirror 504, and the normal of the first mirror 1301 is parallel to the light beam incident thereon or the first The inclination angle between the normal line of the strip mirror 1301 and the light beam incident thereon is γ1; the inclination angle γ1 is not zero;

The incident exit surface of the input and output end 1302, the main plane mirror 504, the first tilt sub-mirror 505, and the first strip mirror 1301 are coplanar and located at a focal plane of the concave mirror 503 5013, the first mirror 1301 is disposed at the other end of the main plane mirror 504 with respect to the input and output end 1302;

A light beam is input from the input and output end 1302, and multiple reflections between the concave mirror 503, the main plane mirror 504, the first tilt sub-mirror 505, and the first mirror 1301 After being output from the input/output terminal 1302, when the normal line of the first mirror 1301 is parallel to the light beam incident thereon, the angle of the light beam incident and emitted from the input/output terminal 1302 is 0 and the direction Conversely, when the inclination angle between the normal line of the first mirror 1301 and the light beam incident thereon is γ1, the angle of the light beam incident and emitted from the input/output terminal 1302 is 2γ1.

In a specific application, the high-efficiency optical path folding device 600 formed by the 4-mirror system provided in this embodiment is equivalent to adding a first mirror 1301 at the position of the output end 502 of the optical path folding system 500 constituted by the 3-mirror system. Reflecting the output beam back to the optical system, and again using the concave mirror 503, the main plane mirror 504 and the first tilt sub-mirror to reflect the beam, except that the spot position will be reversed back to the position of the original input 501, from the input The position of the end 501 is output, that is, the position of the input and output end 1302.

When the normal line of the first mirror 1301 is parallel to the light beam incident thereon, the reflected beam will return along the original path, and output at the input and output end 1302. The output beam is at the same position as the input beam, the angle is the same, and the direction is reversed. to;

When there is a certain angle between the normal line of the first mirror 1301 and the light beam incident thereon, the back beam will be reversely returned, and output at the input and output end 1302. The input beam and the output beam have the same position but different angles. The spatial separation of the input beam and the output beam can be achieved.

The high-efficiency optical path folding device 600 provided in this embodiment is doubled in optical path with respect to the high-efficiency optical path folding device 500 provided in the first embodiment.

It should be understood that the high-efficiency optical path folding device 600 provided in this embodiment has substantially the same working principle as the high-efficiency optical path folding device 500 provided in the first embodiment. In this embodiment, only the difference between the two is emphasized. Other embodiments in the first embodiment can be equally applied to the embodiment, and details are not described herein again.

Embodiment 3

As shown in FIG. 14a and FIG. 14b, on the basis of the second embodiment, the present embodiment provides an efficient optical path folding device 700. A second tilting sub-mirror 1401 is added to the optical pathfolder 600. A tilt sub-mirror 505 and a second tilt sub-mirror 1401 are placed near the origin 509, the input and output end 1302 is restored to the input end 501, and the output end 502 is placed beside the input end 501, so that the first mirror 1301 The normal line has a certain angle with the light beam incident thereon, even if the inclination angle between the normal line of the first mirror 1301 and the light beam incident thereon is γ1; the inclination angle γ1 is not zero.

In the present embodiment, the second inclined sub-mirror 1401 may also be placed side by side with the first inclined sub-mirror 1301 in the second embodiment at the edge of the main plane mirror 503.

In this embodiment, the second tilting sub-mirror 1401 is a plane mirror having a smaller area than the main plane mirror 503, and the normal of the second tilting sub-mirror 1401 and the main plane mirror 504 The inclination angle between the normal lines is θ2; the projections of the inclination angles θ2 and θ1 on the focal plane are not parallel;

An incident surface of the input end 501, an exit surface of the output end 502, the main plane mirror 504, the first tilt sub-mirror 505, the second tilt sub-mirror 1401, and the first The strip mirror 1301 is coplanar and located at a focal plane of the concave mirror 503, and the input end 501 and the output end 502 are located at the same end of the main plane mirror 504, and the first mirror 1301 is opposite The input end 501 and the output end 502 are disposed at the other end of the main plane mirror 504;

a light beam is input from the input end 501, through the concave mirror 503, the main plane mirror 504, the first tilt sub-mirror 1301, the second tilt sub-mirror 1401, and the first strip After multiple reflections between the mirrors 1301, they are output from the output terminal 502.

In a specific application, the high-efficiency optical path folding device 700 formed by the 5-mirror system provided in this embodiment is equivalent to adding a second tilting sub-mirror 1401 to the optical path folding system 600 formed by the 4-mirror system. The normal line of the second inclined sub-reflector 1401 is at an angle to the normal to the main plane mirror 504.

In this embodiment, the normal of the first mirror 1301 is at an angle to the beam incident thereon, and the reflected beam will be reversed but not returned. The normal orientation of the first mirror 1301 is such that the return beam is not incident on the first tilt sub-mirror 505, but is incident on the second tilt sub-mirror 1401, the concave mirror 503, and the main plane mirror 504. The mirror system, since the second tilting sub-mirrors 1401 are at an angle with respect to the tilting direction of the first tilting sub-mirror 505, their projections on the main plane mirror 504 are not parallel, and the return beam locus is in position and forward. The separation of the tracks results in the separation of the output 501 from the position of the input 502, which allows spatial separation of the input beam and the output beam.

A forward 3 mirror system is defined: a first tilt sub-mirror 505, a concave mirror 503, and a main plane mirror 504.

A reverse 3 mirror system is defined: a second tilt sub-mirror 1401, a concave mirror 503, and a main plane mirror 504.

In the present embodiment, when the high-efficiency optical path folding device further includes a driver and an angle measuring device, the driver is the same device as the driver 702 in the first embodiment, and the angle measuring device and the angle measuring device 703 are the same device. The difference is that, in this embodiment, the driver 702 is further configured to drive the second tilting sub-mirror to rotate along the tilting angle thereof to change the magnitude of the tilting angle θ2, thereby causing the light beam to pass from the input end to the The total optical path of the output is variable; the angle measuring device 703 is also used to measure the tilt angle θ2. That is, both the first tilt sub-mirror and the second tilt sub-mirror are driven by the driver 702, and the angle measuring device 703 also measures the angular size.

The high-efficiency optical path folding device 700 provided in this embodiment is doubled in optical path with respect to the high-efficiency optical path folding device 500 provided in the first embodiment, and is the same as the optical path of the high-efficiency optical path folding device 600 provided in the second embodiment. .

It should be understood that the high-efficiency optical path folding device 700 provided in this embodiment has substantially the same working principle as the high-efficiency optical path folding device 600 provided in the second embodiment. In this embodiment, only the difference between the two is emphasized. Other embodiments in the second embodiment can be equally applied to the embodiment, and details are not described herein again.

Embodiment 4

As shown in FIGS. 15a and 15b, on the basis of the third embodiment, the present embodiment provides an efficient optical path folding device 800, and a second mirror 1501 is added to the optical path folder 700.

In this embodiment, the second mirror 1501 is a plane mirror having a smaller area than the main plane mirror 504, and a tilt angle between a normal line of the second mirror 1501 and a light beam incident thereon Is γ2; the inclination angle γ2 is not zero;

An incident surface of the input end 501, an exit surface of the output end 502, the main plane mirror 504, the first tilt sub-mirror 505, the second tilt sub-mirror 1401, the first The strip mirror 1301 and the second mirror 1501 are coplanar and located at a focal plane 506 of the concave mirror 503, and the input end 501, the output end 502 and the second mirror 1501 are located at The same end of the main plane mirror 504, or the first mirror 1301 and the output end 502 are located at the same end of the main plane mirror 504;

a light beam is input from the input end 501, through the concave mirror 503, the main plane mirror 504, the first tilt sub-mirror 505, the second tilt sub-mirror 1401, the first strip After multiple reflections between the mirror 1301 and the second mirror 1501, the output is output from the output terminal 502.

In a specific application, the high-efficiency optical path folding device 800 formed by the 6-mirror system provided in this embodiment is equivalent to adding a second mirror 1501 to the optical path folding system 700 formed by the 5-mirror system. The normal of the two mirrors 1501 is at an angle to the beam incident thereon.

In this embodiment, the normal line of the second mirror 1501 and the light beam incident thereon are at an angle, and the second mirror 1501 is reflected on the basis of the 5 mirror system and is originally outputted by the output terminal 502. The beam, which reflects the beam returned by the reverse 3-mirror system, causes the beam to propagate again in the forward direction. The normal orientation of the second mirror 1501 causes the forwardly propagating beam to be incident on the forward 3-mirror system consisting of the first tilting sub-mirror 505, the concave mirror 503 and the main plane mirror 504, and is forwardly propagated to The first mirror 1301 is reflected by the first mirror 1301, returns to the second mirror 1501 along the reverse 3 mirror system and is reflected, and thus reciprocates until the beam reaches the output 502 and is output.

In this embodiment, the output end 502 can be located at the same end of the main plane mirror 504 as the first mirror 1301, or at the same end of the main plane mirror 504 as the second mirror 1501. The output end 502 and the second mirror 1501 are exemplarily shown in Figures 15a and 15b at the same end of the main plane mirror 504.

The high-efficiency optical path folding device 800 provided in this embodiment can increase the optical path by up to 2 (n-1) with respect to the high-efficiency optical path folding device 500 provided in the first embodiment, wherein n is the beam before being reached at the output end. The number of cycles, n ≥ 1 and n is an integer.

It should be understood that the high-efficiency optical path folding device 800 provided in this embodiment has substantially the same working principle as the high-efficiency optical path folding device 700 provided in the third embodiment. In this embodiment, only the difference between the two is emphasized. Other embodiments in the third embodiment can be equally applied to the embodiment, and details are not described herein again.

Embodiment 5

As shown in FIGS. 16a and 16b, based on the fourth embodiment, the present embodiment provides an efficient optical path folding device 900, which adds a third strip at the output end 502 to the optical path folding device 800. The mirror 1601 removes the output 502 and replaces the input 501 with an input and output 1302.

In this embodiment, the third mirror 1601 is a plane mirror having a smaller area than the main plane mirror 504, and the normal line of the third mirror 1601 is parallel to the light beam incident thereon or the first The inclination angle between the normal line of the three mirrors 1601 and the light beam incident thereon is γ3; the inclination angle γ3 is not zero;

The incident exit surface of the input and output end 1302, the main plane mirror 504, the first tilt sub mirror 505, the second tilt sub mirror 1401, the first strip mirror 1301, The second mirror 1501 and the third mirror are coplanar and located at a focal plane of the concave mirror 503, the input and output end 1302, the second mirror 1501 and the third strip reflection The mirror 1601 is located at the same end of the main plane mirror 504;

a light beam is input from the input and output end 1302, through the concave mirror 503, the main plane mirror 504, the first tilt sub mirror 505, the second tilt sub mirror 1401, the first After multiple reflections between the strip mirror 1301, the second mirror 1501, and the third mirror 1601, the output is output from the input/output terminal 1302, and the normal of the third mirror 1601 When parallel to the light beam incident thereon, the angle of the light beam incident and outgoing from the input/output terminal 1302 is 0 and the direction is opposite; between the normal of the third mirror 1601 and the light beam incident thereon When the tilt angle is γ3, the angle of the light beam incident and emitted from the input/output terminal 1302 is 2γ3.

In a specific application, the high-efficiency optical path folding device 900 constituted by the 7-mirror system provided in this embodiment is equivalent to adding a third mirror 1601 at the position of the output end 502 of the optical path folding system 800 constituted by the 6-mirror system. The output beam is reflected back to the optical system, and the reciprocating reflection is repeated again. The difference is that the position of the spot will be reversely returned to the position of the original input end 501, and output from the position of the input end 501, that is, the position of the input and output end 1302.

When the normal of the third mirror 1601 is parallel to the beam incident thereon, the reflected beam will return along the original path and output at the input and output end 1302. The output beam is at the same position as the input beam, the angle is the same, and the direction is reversed. to;

When there is a certain angle between the normal line of the third mirror 1601 and the light beam incident thereon, the back beam will be reversely returned, and output at the input and output end 1302. The input beam and the output beam have the same position but different angles. The spatial separation of the input beam and the output beam can be achieved.

The high efficiency optical path folding device 900 provided by this embodiment is doubled in optical path with respect to the high efficiency optical path folding device 800 provided in the fourth embodiment.

It should be understood that the high-efficiency optical path folding device 900 provided by the embodiment has the same working principle as the high-efficiency optical path folding device 800 provided in the fourth embodiment. In this embodiment, only the difference between the two is emphasized. Other embodiments in the fourth embodiment can be equally applied to the embodiment, and details are not described herein again.

The above description is only for the preferred embodiment of the present solution, and is not intended to limit the present solution. Any modifications, equivalent replacements, and improvements made within the spirit and principles of the present solution should be included in the scope of protection of the present solution. within.

Claims

An efficient optical path folding device, comprising:

An input for inputting a light beam;

An output for outputting a light beam, the input end being disposed separately from the output end;

a main plane mirror;

a concave mirror having a focal plane, the focal plane to the concave mirror being a focal length f of the concave mirror; the focal plane having an origin, the origin being the principal plane mirror An intersection of an optical system optical axis composed of a concave mirror on the focal plane;

a first tilting sub-reflector having a smaller area than the plane mirror of the main plane mirror, an inclination angle between a normal line of the first inclined sub-mirror and a normal line of the main plane mirror is θ1 The tilt angle θ1 is not zero;

An entrance surface of the input end, an exit surface of the output end, the main plane mirror and the first tilt sub-mirror are coplanar and located at a focal plane of the concave mirror;

A light beam is input from the input end, and is output from the output end through multiple reflections between the concave mirror, the main plane mirror, and the first tilt sub-mirror.
The high efficiency optical path folding device of claim 1 further comprising:

a second tilting sub-reflector having a smaller area than the plane mirror of the main plane mirror, and an inclination angle between a normal line of the second inclined sub-mirror and a normal line of the main plane mirror is θ2 a projection of the inclination angle θ2 and the inclination angle θ1 on the focal plane is not parallel;

a first mirror, which is a plane mirror having an area smaller than the main plane mirror, an inclination angle between a normal line of the first mirror and a light beam incident thereon is γ1; the inclination angle γ1 Not zero;

An entrance surface of the input end, an exit surface of the output end, the main plane mirror, the first tilt sub-mirror, the second tilt sub-mirror and the first mirror are coplanar and located a focal plane of the concave mirror, the input end and the output end are located at the same end of the main plane mirror, and the first mirror is disposed opposite to the input end and the output end The other end of the main plane mirror;

a light beam is input from the input end through the concave mirror, the main plane mirror, the first tilt sub-mirror, the second tilt sub-mirror, and the first mirror After multiple reflections, output from the output.
The high efficiency optical path folding device of claim 2, further comprising:

a second mirror, which is a plane mirror having an area smaller than the main plane mirror, an inclination angle between a normal line of the second mirror and a light beam incident thereon is γ2; the inclination angle γ2 Not zero;

An incident surface of the input end, an exit surface of the output end, the main plane mirror, the first tilt sub-mirror, the second tilt sub-mirror, the first mirror, and the first Two mirrors are coplanar and located in a focal plane of the concave mirror, and the input end, the output end and the second mirror are located at the same end of the main plane mirror, or a mirror and the output end are located at the same end of the main plane mirror;

a light beam is input from the input end through the concave mirror, the main plane mirror, the first tilt sub-mirror, the second tilt sub-mirror, the first mirror, and the After multiple reflections between the second mirrors, they are output from the output.
The high efficiency optical path folding device according to any one of claims 1 to 3, wherein the input beam has a radius A0 and a divergence half angle of β0;

The distance of the first tilt sub-mirror from the origin of the focal plane is greater than the product of the divergence half angle of the input beam and the focal length of the concave mirror β0·f.
The high efficiency optical path folding device according to claim 4, wherein said first tilting sub-mirror is located at said focal plane after said input beam is reflected by said concave mirror for a first or third time The position of the first mirror has a light passing diameter greater than 2β0·f.
The high efficiency optical path folding device according to claim 5, wherein the selection of the oblique angle direction of the first tilting sub-reflector causes the input beam to pass through an even number of reflections of the concave mirror to reach the In the focal plane, the distance from the center of the input beam to the boundary of the first tilted submirror is greater than the radius A0 of the input beam.
The high efficiency optical path folding device according to any one of claims 1 to 3, wherein the input end is a first optical fiber collimator with a first pigtail, and the light beam is collimated by the first optical fiber. Input

Or the input end is a first fiber collimator array with a first pigtail array, and a light beam is input through the first fiber collimator array;

Or the input end is a light passing hole or an opening angle on the main plane mirror, and the light beam enters the input end from the free space;

Alternatively, the input end is connected to the light emitting device through an optical fiber, and the input end inputs a light beam emitted by the light emitting device;

The output end is a second fiber collimator with a second pigtail, and the output beam is output through the second fiber collimator;

Or the output end is a second fiber collimator array with a second pigtail array, and the output beam is output through the second fiber collimator array;

Or the output end is a light passing hole or an opening angle on the main plane mirror, and the output light beam is output from the output end to a free space;

Or the output end is connected to the photodetector through an optical fiber, and the output beam is received by the photodetector;

Alternatively, the output is coupled to the array of photodetectors via an optical fiber, and the output beam is received by the array of photodetectors.
The high efficiency optical path folding device according to any one of claims 1 to 3, further comprising:

a driver for driving the first tilting sub-mirror to rotate in an oblique direction thereof to change the magnitude of the tilting angle θ1 such that a total optical path of the light beam from the input end to the output end is variable;

An angle measuring device for measuring the tilt angle θ1;

Wherein the driver is one of a piezoelectric ceramic type or an electromagnetic type driver, and the angle measuring device is an optical angle measuring device with a measuring laser and a four-quadrant detector.
The high efficiency optical path folding device according to any one of claims 2 to 3, further comprising:

a driver for driving the first tilting submirror and the second tilting submirror to rotate in respective tilting angle directions to change the tilting angle θ1 and the tilting angle θ2 to thereby make the light beam The total optical path from the input to the output is variable;

An angle measuring device for measuring the tilt angle θ1 and the tilt angle θ2;

Wherein the driver is one of a piezoelectric ceramic type or an electromagnetic type driver, and the angle measuring device is an optical angle measuring device with a measuring laser and a four-quadrant detector.
The high efficiency optical path folding device according to claim 1, wherein said output end is located at a position of said focal plane after said input beam is reflected by said concave mirror 4 by a positive integer multiple.
An efficient optical path folding device, comprising:

An input and output terminal for the input beam and the output beam;

a main plane mirror;

a concave mirror having a focal plane, the focal plane to the concave mirror being a focal length f of the concave mirror; the focal plane having an origin, the origin being the principal plane mirror An intersection of an optical system optical axis composed of a concave mirror on the focal plane;

a first tilting sub-reflector having a smaller area than the plane mirror of the main plane mirror, an inclination angle between a normal line of the first inclined sub-mirror and a normal line of the main plane mirror is θ1 The tilt angle θ1 is not zero;

a first mirror, which is a planar mirror having a smaller area than the main plane mirror, a normal of the first mirror being parallel to a beam incident thereon or a normal of the first mirror The inclination angle between the light beams incident thereon is γ1; the inclination angle γ1 is not zero;

The incident exit surface of the input and output ends, the main plane mirror, the first tilt submirror and the first mirror are coplanar and located at a focal plane of the concave mirror, the first strip a mirror is disposed at the other end of the main plane mirror with respect to the input and output end;

a light beam is input from the input and output end, and after the multiple reflection between the concave mirror, the main plane mirror, the first inclined sub-mirror, and the first mirror, Input/output output, when the normal of the first mirror is parallel to the light beam incident thereon, the angle of the light beam incident and outgoing from the input and output ends is 0 and the direction is opposite; the first reflection When the inclination angle between the normal line of the mirror and the light beam incident thereon is γ1, the angle of the light beam incident and outgoing from the input and output ends is 2γ1.
The high efficiency optical path folding device of claim 11 further comprising:

a second tilting sub-reflector having a smaller area than the plane mirror of the main plane mirror, and an inclination angle between a normal line of the second inclined sub-mirror and a normal line of the main plane mirror is θ2 The projections of the tilt angles θ2 and θ1 on the focal plane are not parallel;

a second mirror, which is a plane mirror having an area smaller than the main plane mirror, an inclination angle between a normal line of the second mirror and a light beam incident thereon is γ2; the inclination angle γ2 Not zero;

a third mirror, which is a planar mirror having an area smaller than the main plane mirror, a normal of the third mirror being parallel to a beam incident thereon or a normal of the third mirror The inclination angle between the light beams incident thereon is γ3; the inclination angle γ3 is not zero;

An incident exit surface of the input and output ends, the main plane mirror, the first tilt sub-mirror, the second tilt sub-mirror, the first mirror, the second mirror, and The third mirror is coplanar and located at a focal plane of the concave mirror, and the input and output ends, the second mirror and the third mirror are located in the same plane mirror end;

a light beam is input from the input and output end, through the concave mirror, the main plane mirror, the first tilt sub-mirror, the second tilt sub-mirror, the first mirror, the After multiple reflections between the second mirror and the third mirror, output from the input and output ends, when the normal of the third mirror is parallel to the light beam incident thereon, The angle between the incident and outgoing beams is 0 and the direction is opposite; when the inclination angle between the normal of the third mirror and the beam incident thereon is γ3, from the input and output ends The angle between the incident and outgoing beams is 2 γ3.
The high efficiency optical path folding device according to any one of claims 11 or 12, wherein the input beam has a radius A0 and a divergence half angle of β0;

The distance of the first tilt sub-mirror from the origin of the focal plane is greater than the product of the divergence half angle of the input beam and the focal length of the concave mirror β0·f.
The high efficiency optical path folding device of claim 13 wherein said first tilting submirror is located at said focal plane after said input beam is reflected by said concave mirror for a first or third time The position of the first mirror has a light passing diameter greater than 2β0·f.
The high efficiency optical path folding device according to claim 14, wherein the inclination angle direction of said first inclined sub-mirror is selected such that said input beam passes through an even number of reflections of said concave mirror to reach said In the focal plane, the distance from the center of the input beam to the boundary of the first tilted submirror is greater than the radius A0 of the input beam.
The high-efficiency optical path folding device according to any one of claims 11 to 12, wherein the input and output ends are fiber-optic collimators with pigtails, and the light beam is input and output through the fiber collimator;

Or the input and output ends are an array of fiber collimators with a pigtail array, and the light beam is input and output through the fiber collimator array;

Or the input and output ends are light passing holes or opening angles on the main plane mirror, and the light beam enters the input and output ends from the free space;

Alternatively, the input and output end is connected to the light emitting device and the photodetector through an optical fiber, and the input and output end inputs a light beam emitted by the light emitting device, and the output light beam is received by the photodetector;

Alternatively, the input and output terminals are connected to the photodetector array through an optical fiber, and the output beam is received by the photodetector array.
The optical path folding device according to claim 11 or 12, further comprising:

a driver for driving the first tilting sub-mirror to rotate in an oblique direction thereof to change the magnitude of the tilting angle θ1 such that a total optical path of the light beam from the input end to the output end is variable;

An angle measuring device for measuring the tilt angle θ1;

Wherein the driver is one of a piezoelectric ceramic type or an electromagnetic type driver, and the angle measuring device is an optical angle measuring device with a measuring laser and a four-quadrant detector.
The high efficiency optical path folding device of claim 12, further comprising:

a driver for driving the first tilting submirror and the second tilting submirror to rotate in respective tilting angle directions to change the tilting angle θ1 and the tilting angle θ2 to thereby make the light beam The total optical path from the input to the output is variable;

An angle measuring device for measuring the tilt angle θ1 and the tilt angle θ2;

Wherein the driver is one of a piezoelectric ceramic type or an electromagnetic type driver, and the angle measuring device is an optical angle measuring device with a measuring laser and a four-quadrant detector.