CN109212733B - Optical path folding device - Google Patents
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Abstract
The invention provides an optical path folding device, which is characterized in that on the basis of a confocal optical system consisting of a light beam input end, a light beam output end, a main plane reflector and a concave reflector, an inclined sub reflector is introduced on a focal plane to change the reflection angle of a light beam incident on the inclined sub reflector, so that the light beam is reflected in the confocal optical system for multiple times; the output light beam can maintain the optical characteristics of the input light beam and has higher optical path volume ratio; the variable optical path can be realized by rotating the tilting sub-reflector; the parallel input of multiple beams can be realized by adopting a fiber array collimator mode at the input end; the input end and the output end adopt the fiber array collimator, and part of tail fibers are connected, so that the series connection of optical paths can be realized, and a longer optical path can be realized.
Description
Technical Field
The invention relates to an optical path folding device in the field of optical sensing, in particular to an optical path folding device for gas optical sensing and variable optical path.
Background
In a limited volume, multiple reflection of light beams is realized, so that the light beams can travel through a relatively long optical path, and the optical device has important application in the field of optical sensing, particularly the sensing and analysis field of special gases.
At present, semiconductor tunable laser absorption spectrum analysis (TDLAS for short) and Fourier transform infrared spectrum analysis (FTIR for short) are two main technical routes, wherein the TDLAS is mainly used for performing spectrum analysis in a near infrared band based on tunable laser, and the FTIR is used for performing spectrum analysis in middle and far infrared bands by Fourier transform through a wide-spectrum light source.
In order to achieve sufficient detection accuracy, both TDLAS and FTIR require a long optical path gas cell to allow the beam to transmit sufficient optical path within the desired analysis gas to enhance the absorption lines, and in order to keep the volume of the detection instrument within an acceptable range, the long optical path gas cell needs to take the form of an optical path folding device to reflect the beam as many times as possible within a limited volume to achieve sufficient optical path.
For TDLAS application, due to the small divergence angle of the laser beam, the industry commonly adopts an arrangement of an Herriott cell (APPLID OPTICS/Vol.3, No.4/April 1964), as shown in FIG. 1, the Herriott cell (100) adopts two concave mirrors (103, 104) with the same focal length f to form a reflective cavity, when the incident direction and position of the input light beam at the input end (101) and the distance d of the two concave mirrors along the z direction satisfy certain conditions (generally, an out-of-focus configuration with 0 < d < 2f or 2f < d < 4f is adopted), the light beam will be reflected back and forth multiple times at the two concave mirrors, and finally output from the output end (102). Fig. 2 shows two concave mirrors (203, 204) with reflection points forming a circular spot trajectory (201) in the x-y plane.
For FTIR applications, the beam divergence is Large and the performance of the herriott cell is not satisfactory due to the incoherent configuration characteristics required for the source, which results from the fact that the incoherent beam divergence cannot converge after multiple reflections by the defocusing system, the conventional White cell structure (White, j.u. "Long Optical Paths of Large Aperture" j.opt.soc.am., vol.32, pp285-288, May 1942) is commonly used in the industry, as shown in fig. 3, the White cell (300) consists of three concave mirrors with the same radius of curvature and focal length f, the primary mirror (301) is located on one side, the two secondary mirrors (302, 303) are located on the opposite side of the primary mirror, and the input beam (304) and the output beam (305) are located on both sides of the primary mirror. The two secondary reflectors have a certain inclination angle, the distance between the main reflector and the two secondary reflectors is set to be 2f, so that light beams are reflected and imaged for multiple times back and forth on the main reflector and the two secondary reflectors and finally output from one side of the main reflector. The locus of the spots on the primary mirror is shown in fig. 4, and typically the input beam position (404) is offset from the axis (402) of the primary mirror (401) so that the spots are distributed over two rows of loci (403, 406) to achieve the maximum number of reflections. The output beam position (405) is generally on the other side of the trajectory (406) in line with the input beam.
With the improvement of the gas detection precision requirement in the industry, the requirement on an optical path gas chamber is further improved, a longer optical path (more than 20 meters and even more than 100 meters) needs to be realized in a limited volume, and a herriott chamber and a white chamber are difficult to realize more reflections in a certain volume. There are many improved designs based on the herriott cell and the white cell, such as those proposed by herriott, to achieve more reflection times with astigmatic lenses ("Folded Optical Delay Lines", appl. opt., vol.4, No.8, pp883-889, 1965), but there is a problem that astigmatic lenses are difficult to process, although the subsequent rotation of an astigmatic lens to reduce the processing accuracy requirement (us 5291265, 1994) still does not solve the problem of high processing cost of astigmatic lenses; joel.a.silver et al propose to achieve dense spot distribution, i.e. more reflection times, with a bi-cylindrical mirror (us patent 7477377, 2009), but due to the non-rotationally symmetric nature of the bi-cylindrical mirror, the beam no longer has the same beam characteristics as the input beam after multiple reflections, and cannot be applied in application scenarios where beam characteristics (beam radius, divergence half angle, etc.) are required to be maintained. Although there are some improvements based on the white room, for example, the chinese patent "folding multiple optical path multiple gas cell" (CN102053063B) uses a corner reflector at the output end of the white room to reflect the output beam back along the original path (deviating a small angle), the optical path is doubled, but the input and output ends are too close to each other, which requires more space to separate the input and output beams; meanwhile, the white room uses a secondary reflector with an angle, and after the light beam is reflected for multiple times, aberration has a large influence on the characteristics of the output light beam.
Disclosure of Invention
The invention provides the optical path folding device aiming at the requirements of longer optical path, higher optical path/volume ratio and light beam characteristic keeping input state after long optical path transmission of the optical path folding device in the industry boundary.
As shown in fig. 5, the present invention provides an optical path folding device (500), comprising:
an input end (501) for inputting a light beam;
an output (502) for outputting a light beam;
a primary plane mirror (504);
a concave mirror (503) having a focal plane (506) at a distance (507) from said concave mirror that is the focal length f of the concave mirror; the focal plane also has an origin (509) which is the intersection of the optical axis (508) of the optical system formed by the primary flat mirror and the concave mirror.
A tilting sub-mirror (505) being a facet mirror whose normal forms a tilt angle θ with the normal of said main plane mirror;
the input end, the output end, the main plane reflector and the inclined sub reflector are coplanar and positioned on a focal plane of the concave reflector; the light beam is input from the input end, is reflected for multiple times by the concave reflecting mirror, the main plane reflecting mirror and the inclined sub reflecting mirror, and is finally output from the output end.
From an optical characteristic point of view, due to the use of a confocal system, at the focal plane (506), the radius and the half angle of divergence of the beam will vary between two sets of values, independent of the number of reflections of the concave mirror, and only of its parity. Let the radius of the input beam at the input end be A0Half angle of divergence of beta0The radius of the light beam reaching the focal plane after being reflected by the concave reflector is A1Divergence angle of half beta1The following relationships are present:
A1＝β0·f (1)
β1＝A0/f (2)
the radius of the light beam reaching the focal plane after being reflected by the concave surface reflector twice is A2Half angle of divergence of beta2Can be obtained by applying the formulas (1) and (2) twice:
A2＝β1·f＝(A0/f)·f＝A0 (3)
β2＝A1/f＝(β0·f)/f＝β0 (4)
as can be seen from the formulas (3) and (4), the light beam recovers the characteristics of the input light beam after being reflected by the concave mirror twice and reaching the focal plane (A)0，β0) It is easy to see that the characteristics of the light beam will be the same as the input light beam after even number of times of reflection by the concave reflector; for odd number of times of reflection of the concave mirror, the characteristics of the light beam will take the radius and divergence half angle (A) obtained from (1) and (2)1，β1)。
For the transformation of the position and the angle of the chief ray of the input light beam (relative to the optical axis formed by the main plane reflector and the concave reflector), under the condition of not introducing the inclined sub-reflector (505), the position of the chief ray of the light beam is coincided with the position of the chief ray of the input light beam after the chief ray of the light beam reaches the focal plane after being reflected by the concave reflector for four times, and the angle and the chief ray angle of the input light beam form mirror symmetry about the optical axis; because the position of the light beam is coincident with the position of the input end, the light beam is not reflected by the main plane reflector any more and is output through the input end, so that under the condition of not introducing the inclined sub-reflector (505), the light beam is reflected by the concave reflector at most four times, and the total optical path is greatly limited.
In the invention, on a confocal optical system consisting of a concave reflector (503) and a main plane reflector (504), an inclined sub-reflector (505) is introduced, the position of the inclined sub-reflector deviates from an original point (509) by a certain distance and is positioned at the position where an input light beam reaches a focal plane through the first reflection or the third reflection of the concave reflector, so that the reflection angle of the light beam is changed, and the position of a subsequent even-number reflected light beam on the focal plane is changed after the input light beam is reflected by the concave reflector, while the position of an odd-number reflected light beam on the focal plane is unchanged, so that the positions of all the light beams do not collide with an input end any more, and the multiple reflection of the light beam is realized.
It can be easily verified that, as shown in fig. 6a, after the tilted sub-mirror (605) is introduced and the light beam is reflected for a plurality of times by the concave mirror 1+4n (n is 0, 1, 2, 3 … …) on the focal plane (606) where the main plane mirror (604) is located, the position of the light beam is at the same position, which is denoted as P1(611) (ii) a After the light beam is reflected by the concave reflecting mirror 3+4n (n is 0, 1, 2, 3 … …) times, the position of the light beam is at the same position, which is marked as P3(613) (ii) a After the light beam is reflected by the concave reflecting mirror 4+4n (n is 0, 1, 2, 3 … …) times, the position of the light beam is P4、P8、P12… …, which are aligned with the input beam position P0On a straight line, is marked as L4(610) (ii) a After the light beam is reflected by the concave reflecting mirror 2+4n (n is 0, 1, 2, 3 … …) times, the position of the light beam is P2、P6、P10… …, they are in a straight line, and are marked as L2(612)。
For convenience of illustration, in FIGS. 6a and 6b, the tilted sub-mirror (605) is selected to be at the position P of the focal plane of the light beam after the third reflection by the concave mirror3(613) Its normal line (615) forms an inclination angle theta (616) with the normal line (614) of the main plane mirror (604), and a vector is formed along the direction of the ridge formed by the intersection of the plane formed by the two normal lines and the focal plane (606), which is called asA shift vector Δ P (617), the length of which is defined by:
ΔP＝tan(2θ)·f (5)
easily proven pairs are distributed in L2Upper beam position P2、P6、P10… …, and is distributed over L4Beam position P of0、P4、P8、P12… …, the adjacent beam position interval is Δ P given by equation (5), and L2And L4Parallel to Δ P. It can be seen that Δ P includes the magnitude and direction of the tilt angle θ of the tilted sub-mirror.
The property of the confocal optical system indicates P1(611) And P3(613) Is symmetrical about the focal plane origin (609) such that the tilting sub-mirror (605) does not oppose P1The tilted sub-mirror is displaced from the focal plane origin (609) by a distance greater than P1Or P3Radius of the light beam A1Wherein A is represented by the above formula (1)1＝β0F; meanwhile, in order to ensure that the inclined sub-reflecting mirror can reflect all the light beam energy reaching the inclined sub-reflecting mirror, the light transmission diameter of the inclined sub-reflecting mirror is larger than P1Or P3Beam diameter 2. A of1I.e. 2 beta0·f。
To avoid tilting the sub-mirror (605) pair L2Or L4Interference of the upper beam, the direction of the tilt angle theta being chosen such that the direction of the displacement vector delta P is not at the input (601) and P3(613) Forms a certain included angle with the connecting line direction, after even-numbered concave reflector reflection, the distance from the center of the light beam to the boundary of the tilted sub-reflector is larger than the radius A of the input light beam when the light beam reaches the focal plane0So that L is equal to2Or L4The upper light-passing band whose width is the beam diameter does not overlap with the tilted sub-mirror (605).
The output terminal can be taken at L2Or L4Preferably at L collinear with the input4In other words, the input light beam reaches the focal plane after being reflected by the concave mirror for 4 times of positive integer times, so that the input end (601) and the output end (602) are at L4(610) On both sides of the base. The light-passing hole on the main plane reflector (604) can be used as input end and output endEnd, or primary plane mirror at L4And the opening angle is obtained by cutting the angle at the two sides.
The forms of the light through hole and the opening angle are suitable for the condition of incoherent input light beams with larger divergence angles, and the light beams are input in a free space propagation mode; for the input light beam is coherent light beam with small divergence angle, such as laser, preferably the optical fiber collimator with tail fiber is used as the light beam input end; the end outlet is correspondingly preferably the output light beam of the optical fiber collimator with the tail fiber, and the light detector can also be selected to directly receive the light beam.
In many applications, the optical path of the device is required to be variable, and therefore, the invention also provides an optical path folding device with variable optical path, as shown in fig. 7, on the basis of the confocal optical system consisting of the concave mirror, the main plane mirror, the tilted sub-mirror and the input/output end, the tilted sub-mirror (705) can rotate along the tilting direction, namely, the size of a tilting angle theta (716) formed by the normal (715) of the tilted sub-mirror and the normal (714) of the main plane mirror can be changed, the rotating shaft (718) of the tilted sub-mirror is positioned in the focal plane (706) of the main plane mirror (704), and the tilted sub-mirror is driven to rotate by a driver (719), and the tilting angle theta is measured by an angle measuring device (720).
The variable tilt angle theta results in a variable displacement vector delta P (717), and the light beam can reach the output end through multiple reflections as long as the tilt angle theta is selected to enable the distance between the input end and the output end to be an integral multiple of delta P, so that the purpose of changing the total optical path is achieved.
The actuator (719) may be one of a piezo ceramic type or an electromagnetic type actuator. The angle measuring device (720) can be an optical angle measuring device with measuring laser and a four-quadrant detector, the laser emitted by the device reaches the four-quadrant detector after being reflected by the inclined sub-reflector, and the size and the direction of the inclined angle theta are obtained through the comparison and calculation of the light intensity data of the four-quadrant detector.
In an application scene, sometimes lasers in a plurality of spectral bands are required to be simultaneously input into an optical path folding device to detect different gas components, in the prior art, a wavelength coupler is adopted to couple the lasers with a plurality of wavelengths into a tail fiber, and then the lasers are input through an optical fiber collimator; multiple spectra may be required for thisThe laser beam of the array is input in parallel through a first fiber collimator array (801) with a first tail fiber array, output in parallel through a second fiber collimator array (802) with a second tail fiber array, or received in parallel by using a photodetector array (802), as shown in fig. 8. Since a plurality of light beams input in parallel by the first fiber collimator array (801) have the same angle with respect to the optical axis, the positions of the light beams are the same as P after being reflected by the concave mirror 1+4n (n is 0, 1, 2, 3 … …) for times1(ii) a After the light beam is reflected by the concave reflecting mirror 3+4n (n is 0, 1, 2, 3 … …) times, the position of the light beam is the same as P3(ii) a After being reflected by the concave mirror 4+4n (n is 0, 1, 2, 3 … …) times, the position distribution of the light beam is consistent with a single input condition in the direction of delta P (817), but is spread in the arrangement direction (818) of the first fiber collimator array; after the light beams are reflected for 2+4n (n is 0, 1, 2 and 3 … …) times by the concave reflecting mirror, the positions of the light beams are similar to the position distribution of the light beams formed by 4+4n (n is 0, 1, 2 and 3 … …) times of reflection, the light beams are spread in the delta P direction and the arrangement direction of the first optical collimator array, and the positions of the two groups of light beams are distributed symmetrically about an origin (809) on a focal plane (806).
In order to achieve a longer optical path, the invention also provides a device with series-connected optical paths, on the basis that the input end is a first optical fiber collimator array with a first tail fiber array shown in fig. 8, and the output end is a second optical fiber collimator array with a second tail fiber array, as shown in fig. 9, partial tail fibers in the first and second tail fiber arrays (901, 902) are connected in series through optical fibers to form an input end with only one input tail fiber (903) and an output end with only one output tail fiber (904), in such a way, light beams are input from the input tail fiber (903), and repeatedly input into the optical path folding device after being reflected and connected in series for multiple times by the optical path folding device until being output from the output tail fiber (904). If the first tail fiber array has M tail fibers, the total optical path is M times of the optical path of a single device.
Due to the excellent optical characteristics of the reflection confocal system, the concave reflector can adopt an inexpensive and mature spherical reflector under the condition that the divergence angle of the light beam is not large (such as coherent light); in the case of a beam having a relatively large divergence angle (e.g., incoherent light), an aspherical mirror may be used as the concave mirror.
As can be seen from the foregoing analysis, the optical path folding device provided by the present invention can maintain the same beam characteristics (beam radius, divergence half angle, etc.) as the input beam, and can be used in a scene with a small beam divergence angle and a scene with a large beam divergence angle; compared with Herriott and white rooms, due to the pair P1And P3The optical path folding device provided by the invention can achieve more reflection times, namely a longer optical path and a higher optical path volume ratio under the same volume; because the characteristics of the light beam are maintained after even-number reflection of the concave mirror, the light beam is easier to expand to dense light beams, so that the reflection times and the total optical path are further increased; the total optical path is changed by rotating the angle of the inclined sub-reflecting mirror, so that the optical path variable device is easier to realize in engineering; the optical path folding device with the optical fiber collimator array as the input end provided by the invention avoids the use of a wavelength coupler, can be directly applied to multi-wavelength input, and realizes real-time detection of multiple gas components; the optical path folding device with the optical collimator array as the input end and the output end, provided by the invention, has the advantages that the optical paths are connected in series through the optical fiber connection of the tail fiber to obtain a larger optical path, and the optical path folding device has important value for higher-precision gas detection.
Drawings
FIG. 1 is a schematic diagram of a Herriott cell of the prior art
FIG. 2 is a prior art chart of spot trajectories for reflection points from a Herriott cell
FIG. 3 is a schematic diagram of a white room in the prior art
FIG. 4 is a light beam reflection point spot trace plot for a white room in the prior art
FIG. 5 is a schematic diagram of an optical path folding device according to the present invention
FIG. 6a shows the distribution of the beam position on the focal plane and the position of the tilted sub-mirror of the optical path folding device provided by the present invention
FIG. 6b is an illustration of the tilt direction of the tilted sub-mirror in the optical path folding device provided by the present invention
FIG. 7 is a diagram of an optical path folding device with variable optical path according to the present invention
FIG. 8 is a schematic diagram of an optical path folding device with an input end of a fiber collimator array according to the present invention
FIG. 9 is a diagram of an optical path folding device with an input end and an output end of a fiber collimator array and an optical path connected in series according to the present invention
FIG. 10 optical path folding device embodiment 1 according to the present invention
FIG. 11 optical path folding device example 2 according to the present invention
FIG. 12 optical path folding device embodiment 3 provided by the present invention
Detailed Description
[ example 1]
As shown in fig. 10, the present invention provides an optical path folding device (1000), comprising:
an input terminal (1001) for inputting a light beam;
an output (1002) for outputting a light beam;
a primary plane mirror (1004);
a concave mirror (1003) having a focal plane (1006) that is a distance (1007) from the concave mirror that is a focal length f of the concave mirror; the focal plane also has an origin (1009) which is the intersection of the optical axis (1008) of the primary flat mirror and the concave mirror.
A tilting sub-mirror (1005) being a facet mirror whose normal forms a tilt angle θ with the normal of said main plane mirror;
the input end, the output end, the main plane reflector and the inclined sub reflector are coplanar and positioned on a focal plane of the concave reflector; the light beam is input from the input end, is reflected for multiple times by the concave reflecting mirror, the main plane reflecting mirror and the inclined sub reflecting mirror, and is finally output from the output end.
The input end and the output end are light through holes on the main plane reflector (1004), and light beams are input and output in a free space propagation mode.
The input beam is incoherent light with a radius of A0Half angle of divergence of beta0. The distance of the tilted sub-mirror (1005) from the origin (1009) is taken to be 2 beta0F, and the position where the input beam reaches the focal plane by the third reflection of the concave mirror, the inclination direction of which is parallel to the direction of the line connecting the input end and the output end, and the aperture of which is 3 beta0F, so that the beam diameter 2 β arriving thereon can be covered0F, and leaving a certain redundant aperture; the shortest distance between the edge of the oblique sub-reflector and the connecting line of the input end and the output end is 2 times of the radius of the input light beam, namely 2A0. The arrangement is such that the aperture of the tilting sub-mirror does not interfere with the other beams.
Because the divergence angle of the input light beam is large, the concave reflecting mirror adopts an aspheric reflecting mirror to obtain excellent optical performance.
[ example 2]
This embodiment is similar to embodiment 1, and as shown in fig. 11, differs from embodiment 1 in that:
1. the input end (1101) and the output end (1102) are optical fiber collimators with tail fibers, the input light beam is coherent light, the light beam input to the optical path folding device from the optical fiber collimator is a Gaussian light beam, and the Gaussian light beam has a Gaussian beam waist radius omega and a far field divergence half angle alpha, and the radius of the light beam is defined as A03 omega, half angle of divergence beta03 alpha, so as to cover most of energy of the Gaussian beam, and then the distance of the inclined sub-mirror (1105) from the origin (1109) is 6 alpha.f, and the aperture is 9 alpha.f; the shortest distance from the edge of the oblique sub-reflector to the connecting line of the input end and the output end is 6 omega.
2. The concave mirror (1103) is taken as a spherical mirror.
Taking ω to 0.2mm, f to 200mm, α to 2.5mrad, it is possible to obtain a tilted sub-mirror with a distance from the origin of about 3mm, an aperture of about 4.5mm, and a shortest distance from the edge of the aperture to the line connecting the input and output ends of 1.2 mm. Under the condition of the same adjacent light beam distance, the optical path folding device provided by the embodiment can obtain an optical path which is more than twice of the optical path of a Herriott cell and a white cell, and has a higher optical path volume ratio.
[ example 3]
This example is similar to example 2, as shown in fig. 12, except that: the tilt sub-reflector (1205) can rotate along the tilt direction, namely the size of the tilt angle theta can be changed, the rotating shaft (1218) of the tilt sub-reflector is positioned in a focal plane (1206) where the main plane reflector (1204) is positioned, and is driven to rotate by a piezoelectric ceramic driver (1219), the tilt angle theta is measured by an optical angle measuring device (1220) with measuring laser and a four-quadrant detector, the laser emitted by the device reaches the four-quadrant detector after being reflected by the tilt sub-reflector, and the size and the direction of the tilt angle theta are obtained through comparison calculation of light intensity data of the four-quadrant detector.
The variable tilt angle theta results in a variable displacement vector delta P, and the tilt angle theta is selected so that the distance between the input end and the output end is an integral multiple of delta P, so that the light beam can reach the output end (1202) from the input end (1201), and the purpose of changing the total optical path is achieved.
[ example 4]
Similar to embodiment 2, the optical fiber collimator with pigtails at the input and output ends shown in fig. 11 is replaced by an optical fiber collimator array with a pigtail array, so that simultaneous input and output of multiple beams are realized.
[ example 5]
This embodiment is similar to embodiment 4 in that a part of the pigtails on the input and output fiber collimator array are connected in series by fiber to form an input end having only one input pigtail and an output end having only one output pigtail, in such a manner that the light beam is input from the input pigtail, repeatedly reflected by the optical path folding device and the pigtails connected in series, and then repeatedly input into the optical path folding device until being output from the output pigtail. The input optical fiber collimator array has M tail fibers, and the total optical path is M times of a single optical path.
Claims (16)
1. An optical path folding device, comprising:
an input end for inputting a light beam;
an output for outputting a light beam;
a primary planar mirror;
a concave reflector having a focal plane, the focal plane being spaced from the concave reflector by a focal length f of the concave reflector; the focal plane also has an origin which is the intersection point of the optical axis of the optical system formed by the main plane reflector and the concave reflector;
a tilting sub-mirror, which is a plane mirror, the normal line of which forms a tilt angle theta with the normal line of the main plane mirror, wherein theta is not equal to 0 degree;
the input end, the output end, the main plane reflector and the inclined sub reflector are coplanar and positioned on a focal plane of the concave reflector; the light beam is input from the input end, is reflected for multiple times by the concave reflecting mirror, the main plane reflecting mirror and the inclined sub reflecting mirror, and is finally output from the output end.
2. An optical path folding device as claimed in claim 1, characterized in that the radius of the input beam is a0Half angle of divergence of beta0(ii) a The distance of the position of the tilted sub-reflector deviating from the origin of the focal plane is greater than the product beta of the divergence half angle of the input light beam and the focal length of the concave reflector0•f。
3. An optical path folding device as claimed in claim 2, wherein said tilted sub-mirror is located at a position where the input beam reaches the focal plane after being reflected for the first time or the third time by said concave mirror, and the light passing diameter thereof is larger than 2 β0•f。
4. An optical path folding device as claimed in claim 3, wherein the directions of the tilt angles of the tilted sub-mirrors are selected such that the distance from the center of the beam to the boundary of the tilted sub-mirror when it reaches the focal plane after being reflected by the concave mirror for an even number of times is larger than the radius A of the input beam0。
5. An optical path folding device as claimed in claim 1, wherein said input and output ends are clear holes or open angles on said primary plane mirror.
6. An optical path folding device as claimed in claim 1 in which the output is selected to be at a position where the input beam reaches the focal plane after being reflected by the concave mirror a positive integer number of times 4 times.
7. An optical path folding device as claimed in claim 1, wherein said input end is a first fiber collimator with a pigtail through which the light beam is input; the output end is a second optical fiber collimator with a tail fiber or an optical detector, and the output light beam is output through the second optical fiber collimator or directly received by the optical detector.
8. An optical path folding device as claimed in claim 1, wherein the tilting sub-mirror is rotatable in a direction of its tilting angle, and further comprising an actuator for driving the tilting sub-mirror to rotate, the magnitude of the tilting angle θ being variable, thereby enabling the total optical path of the light beam from the input end to the output end to be variable.
9. An optical path folding device as claimed in claim 8 wherein said actuator is one of a piezo ceramic type or an electromagnetic type actuator.
10. An optical path folding device according to claim 8, further comprising an angle measuring means for measuring the tilt angle θ of said tilted sub-mirror.
11. An optical path folding device as claimed in claim 10, characterized in that the angle measuring means are optical angle measuring means with a measuring laser and a four-quadrant detector.
12. An optical path folding device according to claim 1, wherein the input end is a first fiber collimator array with a first pigtail array through which the light beams are input, and a plurality of light beams input in parallel by the first fiber collimator array have the same angle with respect to the optical axis.
13. An optical path folding device as claimed in claim 12 in which the output is a second array of fibre collimators with a second array of pigtails; the output light beams are output through the second optical fiber collimator array.
14. An optical path folding device as claimed in claim 12 in which the output is a photodetector array, the output beam being received directly by the photodetector array.
15. The optical path folding device according to claim 13, wherein the second pigtail array of the output end and a part of pigtails in the first pigtail array of the input end are connected by optical fibers and are connected in series to form an input end with only one input pigtail and an output end with only one output pigtail, and the light beam is input from the input pigtail, repeatedly input into the optical path folding device after being reflected multiple times by the optical path folding device and the pigtails connected in series until being output from the output pigtail.
16. The optical path folding device of any of claims 1-15 wherein the concave mirror is one of a spherical mirror or an aspherical mirror.
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| CN201710548550.0A CN109212733B (en) | 2017-07-04 | 2017-07-04 | Optical path folding device |
| PCT/CN2018/089621 WO2019007175A1 (en) | 2017-07-04 | 2018-06-01 | Efficient optical path folding device |
| CN201880000495.4A CN109477953B (en) | 2017-07-04 | 2018-06-01 | Efficient optical path folding device |
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| CN201710548550.0A CN109212733B (en) | 2017-07-04 | 2017-07-04 | Optical path folding device |
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| CN109597192B (en) * | 2018-12-21 | 2024-02-06 | 江苏旭海光电科技有限公司 | High-efficiency optical path folding device and miniaturized high-sensitivity gas sensor |
| CN110108692B (en) * | 2019-04-16 | 2022-01-18 | 徐州旭海光电科技有限公司 | Efficient optical path folding device, Raman detector and system |
| WO2021120187A1 (en) * | 2019-12-20 | 2021-06-24 | 徐州旭海光电科技有限公司 | Compact sensor device |
| CN111562237A (en) * | 2020-05-26 | 2020-08-21 | 中国科学院合肥物质科学研究院 | CO based on double-beam cavity enhanced spectroscopy technology2、N2O stable isotope simultaneous detection device and method |
| CN111896475A (en) * | 2020-07-29 | 2020-11-06 | 东北大学秦皇岛分校 | Light path range-extending type photoacoustic cell for photoacoustic spectrum trace gas detection |
| CN112649389B (en) * | 2020-12-07 | 2022-03-08 | 珠海格力电器股份有限公司 | Sensor optical path component, gas sensor, measuring method and air conditioning system |
| CN113484266B (en) * | 2021-05-28 | 2023-01-17 | 汉威科技集团股份有限公司 | Optical path multiplying device and optical path multiplying gas absorption cell |
| CN113654992B (en) * | 2021-08-27 | 2024-10-29 | 江苏旭海光电科技有限公司 | High-efficiency optical path folding device and optical path amplifying Fourier transform spectrometer |
| GB2628672A (en) * | 2023-03-31 | 2024-10-02 | Servomex Group Ltd | Method, apparatus and system for compact optical gas absorption measurements |
Family Cites Families (10)
| Publication number | Priority date | Publication date | Assignee | Title |
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| US5255112A (en) * | 1990-12-20 | 1993-10-19 | Hitachi, Ltd. | Optical scanning apparatus and system |
| US5440143A (en) * | 1994-02-25 | 1995-08-08 | On-Line Technologies, Inc. | Folded-path optical analysis gas cell |
| DE19528919A1 (en) * | 1995-08-07 | 1997-02-20 | Microparts Gmbh | Microstructured infrared absorption photometer |
| DE10144808A1 (en) * | 2001-09-12 | 2003-03-27 | Pierburg Instr Gmbh | Infrared gas analysis instrument includes adjustable grating in beam path between transmitter and receiver, which can adopt differing angular positions |
| GB0213326D0 (en) * | 2002-06-11 | 2002-07-24 | Edinburgh Instr | Gas sensors |
| CN101562310B (en) * | 2009-05-04 | 2010-09-01 | 北京国科世纪激光技术有限公司 | Passive mode-locking picosecond laser |
| CN104181146A (en) * | 2013-05-22 | 2014-12-03 | 中国科学院光电研究院 | Multipulse laser-induced breakdown spectrum on-line detection system |
| CN203324174U (en) * | 2013-06-24 | 2013-12-04 | 中国石油大学(北京) | Multi-optical-path air chamber used in terahertz system |
| US20150062572A1 (en) * | 2013-09-05 | 2015-03-05 | Goodrich Corporation | White cell for fluid detection |
| CN206057173U (en) * | 2016-06-02 | 2017-03-29 | 中科华仪科技(深圳)有限公司 | Vehicular drunk driving laser detector and system |
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| CN109477953B (en) | 2021-02-19 |
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Address after: No.99, Xuhai Road, Xuzhou Economic and Technological Development Zone, Xuzhou City, Jiangsu Province, 221004 Patentee after: Jiangsu Xuhai Photoelectric Technology Co.,Ltd. Address before: No.99, Xuhai Road, Xuzhou Economic and Technological Development Zone, Xuzhou City, Jiangsu Province, 221004 Patentee before: XUZHOU XUHAI OPTO-ELECTRONIC TECHNOLOGIES Co.,Ltd. |