An efficient ultraviolet fluorescence collection imaging system

Abstract

The utility model discloses a kind of efficient ultraviolet fluorescence collection imaging systems, including imaging lens sleeve, still including fluorescence signal detector, second ultraviolet lenticular lens, first ultraviolet lenticular lens and spherical mirror sequentially arranged, imaging lens sleeve two ends are light inlet end and light outlet end respectively, first ultraviolet lenticular lens is arranged at the light inlet end of imaging lens sleeve, second ultraviolet lenticular lens is arranged in imaging lens sleeve, the focal length of first ultraviolet lenticular lens between first ultraviolet lenticular lens and spherical mirror coincides with the curvature center of first ultraviolet lenticular lens.The utility model is combined by increasing spherical mirror and conventional imaging lens, increase the solid angle of fluorescence collection, thereby improve the collection efficiency of fluorescence;The length of imaging system is adjustable, can satisfy the use scene when the distance from fluorescence signal detector to imaging system is fixed.

Description

Technical Field

[0001] This invention belongs to the field of precision optics and ultraviolet imaging technology, and relates to a high-efficiency ultraviolet fluorescence collection imaging system, which is suitable for applications such as ion clocks, quantum information experiments and high-resolution ultraviolet spectral analysis. Background Technology

[0002] Ultraviolet fluorescence imaging and detection are crucial components in high-precision ion spectroscopy experiments, widely applied in cutting-edge physics experiments such as ion clock performance evaluation, quantum state detection, and ion trap state readout. For example, in mercury ion optical clocks, efficient collection of ultraviolet fluorescence signals in the 254 nm band is required; in calcium ion optical clocks, efficient collection of fluorescence at 397 nm is needed; in quantum information and quantum computing research, commonly used ions such as calcium and beryllium ions require ultraviolet fluorescence imaging systems to collect fluorescence signals; in systems with high-charge ions, the fluorescence wavelength may further extend to 200 nm or even below 180 nm. Due to the short wavelength and high energy of ultraviolet light, conventional visible light or near-infrared imaging systems are inadequate for related detection tasks.

[0003] Existing ultraviolet fluorescence imaging systems mainly face the following challenges:

[0004] 1. Solid angle limitation: Traditional imaging systems based on single lenses or low numerical aperture objectives are limited by a limited solid angle, making it difficult to meet the demand for high-efficiency detection in low signal-to-noise ratio environments. This is especially true when ions are highly localized (e.g., trapped in radio frequency ion traps), where it is necessary to collect as many fluorescent photons scattered from all directions as possible.

[0005] 2. In traditional imaging systems based on single lenses or low numerical aperture objectives, the larger the solid angle, the shorter the imaging object distance. During ion trap readout, ion trapping is achieved by using a stable electrostatic and radio frequency trapping field to confine ions at the center of the ion trap. The ion trap is highly sensitive to the potential of its environment. If other high potentials exist near the ion trap (such as the potential on the imaging lens), the potential field environment at the center of the ion trap will change, pushing the ions away from the center and making the trapping unstable. Furthermore, the potential on the imaging lens is usually variable (affected by ultraviolet light power, etc.), which will also change the position of the ions, severely affecting the stable trapping of ions.

[0006] In summary, there is an urgent need for an ultraviolet fluorescence collection and imaging system with a wide solid angle collection capability, long object distance, and simple structure, in order to improve fluorescence detection sensitivity and meet the stringent requirements of ion clock and quantum optics experiments for ultraviolet optical systems. Utility Model Content

[0007] The purpose of this invention is to provide a highly efficient ultraviolet fluorescence collection and imaging system to address the aforementioned problems in the existing technology.

[0008] The above-mentioned objectives of this utility model are achieved through the following technical means:

[0009] A high-efficiency ultraviolet fluorescence collection imaging system includes an imaging lens sleeve, and further includes a fluorescence signal detector, a second ultraviolet biconvex lens, a first ultraviolet biconvex lens, and a spherical reflector arranged sequentially. The two ends of the imaging lens sleeve are the light-inlet end and the light-outlet end, respectively. The first ultraviolet biconvex lens is disposed at the light-inlet end of the imaging lens sleeve, and the second ultraviolet biconvex lens is disposed inside the imaging lens sleeve. The focal length of the first ultraviolet biconvex lens located between the first ultraviolet biconvex lens and the spherical reflector coincides with the curvature center of the first ultraviolet biconvex lens.

[0010] The imaging lens sleeve has a lens adjustment hole on its side wall and an inner wall thread on its inner wall. The imaging lens sleeve has two pairs of retaining rings inside. The outer ring of each retaining ring has a retaining ring external thread that matches the inner wall thread. The first ultraviolet biconvex lens is engaged between one pair of retaining rings, and the second ultraviolet biconvex lens is engaged between the other pair of retaining rings.

[0011] There are two lens adjustment holes, which are symmetrically distributed with the central axis of the imaging lens sleeve as the axis of symmetry.

[0012] The spherical mirror has a reflective layer on its reflective surface, and the reflective layer is made of MgF2.

[0013] An adjustable aperture is provided at the light-emitting end of the imaging lens sleeve.

[0014] The adjustable aperture includes a cylindrical aperture housing and aperture blades disposed inside the aperture housing. One end of the aperture housing is provided with an external thread that is adapted to connect with the inner wall thread.

[0015] The imaging lens sleeve has a sleeve fixing threaded hole on its side wall.

[0016] The sleeve fixing threaded hole is two, and the two sleeve fixing threaded holes are symmetrically distributed with the central axis of the imaging lens sleeve as the axis of symmetry.

[0017] The fluorescence signal detector is located at the focal length of the second ultraviolet biconvex lens.

[0018] Compared with the prior art, this utility model has the following advantages:

[0019] 1. This utility model increases the solid angle of fluorescence collection by combining a spherical reflector with a traditional imaging lens, thereby improving the fluorescence collection efficiency;

[0020] 2. This invention increases the solid angle of fluorescence collection, thus providing a longer imaging object distance compared to traditional imaging systems when the solid angle of fluorescence collection is the same.

[0021] 3. The length of the imaging system of this utility model is adjustable, which can meet the usage scenarios when the distance from the fluorescence signal detector to the imaging system is fixed.

[0022] 4. This utility model has a simple structure and is easy to operate. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the structure of this invention during ion fluorescence collection;

[0024] Figure 2 This is a schematic diagram of the structure in which the first ultraviolet biconvex lens and the second ultraviolet biconvex lens are fixed to the imaging lens sleeve by a retaining ring.

[0025] Among them, 1-spherical mirror; 2-trapped ion position; 3-first ultraviolet biconvex lens; 4-second ultraviolet biconvex lens; 5-imaging mirror sleeve; 6-fixing retaining ring; 7-adjustable aperture; 8-fluorescence signal detector; 51-lens adjustment hole; 52-sleeve fixing threaded hole. Detailed Implementation

[0026] To facilitate understanding and implementation of this utility model by those skilled in the art, the present utility model will be further described in detail below with reference to embodiments. It should be understood that the embodiments described herein are only for illustration and explanation of this utility model and are not intended to limit this utility model.

[0027] Example 1:

[0028] like Figure 1 As shown, a high-efficiency ultraviolet fluorescence collection imaging system includes a spherical mirror 1, a first ultraviolet biconvex lens 3, a second ultraviolet biconvex lens 4, an imaging lens sleeve 5, a fixing ring 6, and an adjustable aperture 7.

[0029] The spherical mirror 1 is a concave mirror with a radius of curvature D of 75 mm. The spherical mirror 1 reflects light emitted from the center of curvature at a solid angle of approximately 0.84 spherical degrees. The reflecting surface of the spherical mirror 1 is provided with a reflective layer made of MgF2, and the ultraviolet reflectivity of the reflective layer is over 90%.

[0030] The first ultraviolet biconvex lens 3 has a diameter of 50.8 mm, a focal length of 75 mm, a thickness of 12.5 mm at its thickest point in the center, and is made of fused silica. It can transmit ultraviolet light down to a minimum wavelength of 180 nm.

[0031] The second ultraviolet biconvex lens 4 has a diameter of 50.8 mm, a focal length of 150 mm, and a thickness of 7.8 mm at its thickest point in the center. The material of the second ultraviolet biconvex lens 4 is also fused silica.

[0032] like Figure 2 As shown, the imaging lens sleeve 5 is a cylindrical tube with an inner diameter of 50.8 mm, an outer diameter of 56 mm, and a length of approximately 60 mm. The imaging lens sleeve 5 is open at both ends and has internal threads on its inner wall; preferably, the internal threads are standard SM2 internal threads. A lens adjustment hole 51 is cut into the side wall of the imaging lens sleeve 5. Figure 2 51), which facilitates external adjustment of the internal lens position. The side wall of the imaging lens sleeve 5 is also provided with a sleeve fixing threaded hole 52, which can be an M6 threaded hole (…). Figure 2 52), used to fix the entire imaging lens sleeve 5 to the external support frame.

[0033] In some embodiments, there are two lens adjustment holes 51, which are waist-shaped holes, and the two lens adjustment holes 51 are symmetrically distributed about the central axis of the imaging lens sleeve 5. There are also two sleeve fixing threaded holes 52, which are symmetrically distributed about the central axis of the imaging lens sleeve 5.

[0034] The retaining ring 6 has an inner diameter of 46mm, an outer diameter of 50.8mm, and a thickness of 2mm. The outer ring of the retaining ring 6 is provided with a retaining ring external thread that is compatible with the inner wall thread. Preferably, the retaining ring external thread is an SM2 external thread.

[0035] The adjustable aperture 7 includes a cylindrical aperture housing and aperture blades disposed inside the aperture housing. One end of the aperture housing is provided with an SM2 external thread that is adapted to connect with the inner wall thread for fixing to the rear end of the imaging lens sleeve 5. The aperture aperture diameter of the aperture blades of the adjustable aperture 7 is 2mm to 25mm.

[0036] When this invention is applied to trapped ion fluorescence spectroscopy measurement, such as Figure 1 As shown, the ion trapping position 2 is located between the first ultraviolet biconvex lens 3 and the spherical mirror 1. The spherical mirror 1 is located in front of the first ultraviolet biconvex lens 3. The focal point of the first ultraviolet biconvex lens 3 facing the spherical mirror 1 coincides with the center of curvature of the spherical mirror 1. The ion trapping position 2 is located at the point where the focal point of the first ultraviolet biconvex lens 3 facing the spherical mirror 1 coincides with the center of curvature of the spherical mirror 1. The spherical mirror 1 is placed on one side of the ion trapping position 2.

[0037] The fluorescence emitted from the trapped ion position 2 is emitted in all directions. The fluorescence reaching the spherical mirror 1 in each direction is perpendicular to the reflecting surface of the spherical mirror 1, so that the fluorescence reaching the spherical mirror 1 returns along the same path and is emitted in the opposite direction to the other side of the trapped ion position 2. At this time, the fluorescence will reach the first ultraviolet biconvex lens 3. Since the distance from the trapped ion position 2 is exactly at the focal length of the first ultraviolet biconvex lens 3, the fluorescence emitted from the trapped ion position 2 and returned by the spherical mirror 1 will become parallel light when passing through the first ultraviolet biconvex lens 3 and continue to propagate. Then it will reach the second ultraviolet biconvex lens 4, and be refocused or imaged under the action of the second ultraviolet biconvex lens 4. The position after focusing and imaging is the focal position of the second ultraviolet biconvex lens 4, that is, the distance from the center of the second ultraviolet biconvex lens 4 is 150mm. A fluorescence signal detector 8 (which can be a photomultiplier tube or an electron-enhanced CCD) is placed at this position. Meanwhile, during this process, the fluorescence focused by the second ultraviolet biconvex lens 4 will first pass through an aperture stop placed at the rear end of the sleeve. The aperture of this aperture stop is adjustable and can be changed according to actual needs, thereby changing the light transmission aperture of the entire optical system and filtering stray light.

[0038] The first ultraviolet biconvex lens 3 is fixed in the imaging lens sleeve 5. First, a retaining ring 6 is screwed into the imaging lens sleeve 5. Then, the first ultraviolet biconvex lens 3 is placed in the imaging lens sleeve 5. Then, another retaining ring 6 is screwed into the imaging lens sleeve 5 and tightened to press on the first ultraviolet biconvex lens 3, thus fixing the first ultraviolet biconvex lens 3 between the two retaining rings 6.

[0039] The second ultraviolet biconvex lens 4 is fixed to the imaging lens sleeve 5 using the same method. The center distance between the second ultraviolet biconvex lens 4 and the center distance between the first ultraviolet biconvex lens 3 is L, which is adjustable from 10mm to 50mm. While keeping the distances of other components constant, the length of the entire imaging system can be adjusted by changing the distance between the first ultraviolet biconvex lens 3 and the second ultraviolet biconvex lens 4. In some applications, the distance from the fluorescence signal detector 8 to the imaging lens sleeve 5 is fixed. In this case, the fluorescence signal detector 8 may not be in the optimal detection position (i.e., it is not located at the focal length of the second ultraviolet biconvex lens 4). Adjusting the length of the entire imaging system can then place the fluorescence signal detector 8 in the optimal detection position.

[0040] When the fluorescence emitted from the trapped ion site 2 is emitted isotropically in all directions, fluorescence from two directions can be collected. The overall fluorescence collection efficiency is twice that of the conventional method without a spherical reflector. In this embodiment, the solid angle for fluorescence collection reaches 2 × 0.36 = 0.72 spherical angles. Therefore, the present invention greatly increases the fluorescence collection efficiency of the entire optical system.

[0041] According to the principles of geometric optics, the shorter the imaging object distance, the larger the solid angle of light that the optical system can collect. This invention, by incorporating a spherical reflector 1, increases the solid angle of fluorescence collection, thus providing a longer imaging object distance compared to traditional imaging systems while maintaining the same solid angle. In this embodiment, the focal length of the first ultraviolet biconvex lens 3 is 75mm, meaning the imaging object distance is 75mm. Traditional imaging lenses require an imaging object distance of less than 46mm to achieve the same solid angle.

[0042] The specific embodiments described in this utility model are merely illustrative examples of the spirit of this utility model. Those skilled in the art to which this utility model pertains may make various modifications or additions to the described specific embodiments or use similar methods to replace them, but without departing from the spirit of this utility model or exceeding the scope defined by the appended claims.

Claims

1. A high-efficiency ultraviolet fluorescence collection imaging system, comprising an imaging lens sleeve (5), characterized in that, It also includes a fluorescent signal detector (8), a second ultraviolet biconvex lens (4), a first ultraviolet biconvex lens (3), and a spherical reflector (1) arranged in sequence. The two ends of the imaging lens sleeve (5) are the light inlet end and the light outlet end, respectively. The first ultraviolet biconvex lens (3) is set at the light inlet end of the imaging lens sleeve (5), and the second ultraviolet biconvex lens (4) is set inside the imaging lens sleeve (5). The focal length of the first ultraviolet biconvex lens (3) located between the first ultraviolet biconvex lens (3) and the spherical reflector (1) coincides with the curvature center of the first ultraviolet biconvex lens (3).

2. The high-efficiency ultraviolet fluorescence collection imaging system according to claim 1, characterized in that, The imaging lens sleeve (5) has a lens adjustment hole (51) on its side wall and an inner wall thread on its inner wall. The imaging lens sleeve (5) has two pairs of retaining rings (6) inside. The outer ring of each retaining ring (6) has a retaining ring external thread that matches the inner wall thread. The first ultraviolet biconvex lens (3) is held between one pair of retaining rings (6), and the second ultraviolet biconvex lens (4) is held between the other pair of retaining rings (6).

3. The high-efficiency ultraviolet fluorescence collection imaging system according to claim 2, characterized in that, There are two lens adjustment holes (51), and the two lens adjustment holes (51) are symmetrically distributed with the central axis of the imaging lens sleeve (5) as the axis of symmetry.

4. The high-efficiency ultraviolet fluorescence collection imaging system according to claim 1, characterized in that, The spherical mirror (1) has a reflective layer on its reflective surface, and the reflective layer is made of MgF2.

5. The high-efficiency ultraviolet fluorescence collection imaging system according to claim 2, characterized in that, An adjustable aperture (7) is provided at the light-emitting end of the imaging lens sleeve (5).

6. The high-efficiency ultraviolet fluorescence collection imaging system according to claim 5, characterized in that, The adjustable aperture (7) includes a cylindrical aperture housing and aperture blades disposed inside the aperture housing. One end of the aperture housing is provided with an external thread that is adapted to connect with the inner wall thread.

7. The high-efficiency ultraviolet fluorescence collection imaging system according to claim 6, characterized in that, The imaging lens sleeve (5) has a sleeve fixing threaded hole (52) on its side wall.

8. The high-efficiency ultraviolet fluorescence collection imaging system according to claim 7, characterized in that, There are two sleeve fixing threaded holes (52), and the two sleeve fixing threaded holes (52) are symmetrically distributed with the central axis of the imaging mirror sleeve (5) as the axis of symmetry.

9. The high-efficiency ultraviolet fluorescence collection imaging system according to claim 1, characterized in that, The fluorescence signal detector (8) is located at the focal length of the second ultraviolet biconvex lens (4).

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