前沿分享|双激光拉曼光谱仪的设计与制作

The combination of two spectrometers in dual-laser Raman devices without the need for moving parts represents a significant advancement. This study focuses on design and fabrication of a dual spectrometer with no moving components, allowing data to be gathered using a single detector. This instrument consists of two Czerny–Turner optical arrangements which is symmetrically merged. Dual spectrometer single detector has two light inputs, each of them, concentrating the light separately on a one linear charge-coupled device detector through two independent optical paths. In this innovative spectrometer design, no optical moving parts are used, and therefore, the wavelength displacement error in repeating the spectroscopic experiment is zero. The independent nature of the optical paths enables the optimization of each spectrometer arrangement without affecting the other. The final spectrometer has a spectral resolution of 4.6 and 6.11 cm− 1 for Full Width at Half Maximum across the wavelength ranges of 532 to 708 nm and 784.65 to 1100 nm, respectively. Switching between the two different acquisition setups can be done seamlessly and quickly, with the ability to record approximately 2000 spectra per second. Standard neon and mercury-argon lamps’ atomic radiation spectra, along with Raman scattering data from a cyclohexane standard sample, were successfully recorded using laser wavelengths of 532 nm and 784.65 nm.双激光拉曼器件中两个光谱仪的组合，而不需要移动部件，这是一个重大的进步。本研究的重点是设计和制造无移动组件的双光谱仪，允许使用单个探测器收集数据。该仪器由两个对称合并的切尔尼-特纳光学排列组成。双光谱仪单探测器有两个光输入，每个光输入分别将光通过两个独立的光路集中在一个线性电荷耦合器件探测器上。在这种创新的光谱仪设计中，没有使用光学运动部件，因此，重复光谱实验的波长位移误差为零。光路的独立性使每个光谱仪的排列最优化而不影响其他。最终光谱仪在532 ~ 708 nm和784.65 ~ 1100 nm波长范围内，光谱分辨率分别为4.6和6.11 cm − 1 。两种不同采集装置之间的切换可以无缝、快速地完成，每秒可以记录大约2000个光谱。使用波长分别为532 nm和784.65 nm的激光，成功地记录了标准氖灯和汞氩灯的原子辐射光谱，以及环己烷标准样品的拉曼散射数据。

Introduction 介绍

The design and construction of spectrometers with unique capabilities and applications in various scientific fields such as biology, physics, and chemistry are important. Recent studies have focused on integrating multiple spectrometers into a single system, resulting in numerous benefits. These advantages include the ability to use portable systems for quick analysis1, lower manufacturing costs, fast and precise spectrometry2,3, and eliminating the need for repetitive wavelength calibration4,5. The integration of various molecular and elemental spectroscopy techniques is one of the key focuses in the design and construction of spectrometers6,7. Recent articles have discussed the combination of laser-induced breakdown spectroscopy (LIBS) and Raman methods in the Mars rover, resulting in a device capable of capturing a broad range of atomic and molecular data in a compact and lightweight design8,9. Additionally, NASA’s Super Cam instrument showcased in the Mars probe demonstrated the incorporation of four different remote sensing techniques10. Another area of research in specialized spectrometer design involves creating devices with optimized selection intervals for specific applications. In some studies, researchers have developed super-high spectral resolution optical spectrometers with zero coma aberration over a broad wavelength range by using multiple sub-gratings11,12,13.

设计和建造具有独特功能的光谱仪并将其应用于生物学、物理学和化学等各个科学领域是非常重要的。最近的研究集中在将多个光谱仪集成到一个系统中，从而带来许多好处。这些优点包括使用便携式系统进行快速分析的能力1、较低的制造成本、快速和精确的光谱测定2、3以及消除对重复波长校准的需要4、5。各种分子和元素光谱技术的集成是光谱仪6、7的设计和构造中的关键焦点之一。最近的文章讨论了激光诱导击穿光谱（LIBS）和拉曼方法在火星探测器的组合，从而在一个紧凑和轻便的设计，能够捕捉广泛的原子和分子数据的设备8，9。此外，在火星探测器中展示的美国航天局超级凸轮仪器展示了四种不同遥感技术的结合10。专业光谱仪设计的另一个研究领域涉及为特定应用创建具有优化选择间隔的设备。在一些研究中，研究人员已经通过使用多个子光栅11、12、13开发出在宽波长范围内具有零慧形像差的超高光谱分辨率光谱仪。

In dual laser Raman systems, it is essential to use two spectrometers to efficiently record the Raman spectrum. Each spectrometer is dedicated to recording the distinct Raman spectrum produced by its respective laser source. The most expensive component of Raman spectrometers is the detector. By using a spectrometer that can record Raman spectra from both lasers with only one detector, cost-effective measures can be taken. Additionally, having a single detector enables easy comparisons of results from both spectrometers. Traditional systems typically use moving gratings to disperse light onto the detector. However, the process of shifting the grating is time-consuming and may lead to calibration errors, requiring frequent recalibrations14,15,16,17. By using a single spectrometer that covers both laser Raman ranges without any movable parts, the testing process can be significantly sped up. This also eliminates the need for frequent recalibrations, reducing the risk of calibration errors. Another solution for accommodating the required range for two Raman configurations without any moving parts is the Echelle setup. Research indicates that using the Echelle arrangement in Raman spectroscopy may lead to a lower signal-to-noise ratio18. Although concentrating the signal on one dimension of the detector can somewhat improve the signal-to-noise ratio (SNR), it does not achieve optimal signal intensity. The inherent weakness of the Raman signal highlights the need for a highly sensitive spectrometer, which is why many researchers prefer theCzerny–Turner (C–T) arrangement in this field19,20.在双激光拉曼系统中，必须使用两台光谱仪来有效地记录拉曼光谱。每个光谱仪都专门记录由其各自的激光源产生的不同拉曼光谱。拉曼光谱仪最昂贵的部件是探测器。通过使用一个光谱仪，可以记录来自两个激光器的拉曼光谱，只有一个探测器，可以采取经济有效的措施。此外，有一个单一的探测器可以方便地比较两个光谱仪的结果。传统的系统通常使用移动光栅将光分散到探测器上。然而，移动光栅的过程是耗时的，并可能导致校准误差，需要频繁的重新校准 14,15,16,17。通过使用一个覆盖两个激光拉曼范围而没有任何可移动部件的光谱仪，测试过程可以显着加快。这也消除了频繁重新校准的需要，降低了校准错误的风险。另一种在没有任何移动部件的情况下容纳两个拉曼配置所需范围的解决方案是梯队设置。研究表明，在拉曼光谱中使用梯队排列可以导致较低的信噪比 18 。虽然将信号集中在检测器的一个维度上可以在一定程度上提高信噪比，但不能达到最优信号强度。拉曼信号固有的弱点突出了对高灵敏度光谱仪的需求，这就是为什么许多研究人员在该领域更倾向于采用泽尼-特纳（C-T）排列 19,20 。

To increase flexibility in adjusting the positioning and angle of optical elements, a system that combines two (C–T) configurations is used. This setup meets the need for spectral resolution in the specified range without introducing any additional aberrations21.为了增加调整光学元件位置和角度的灵活性，采用了两种（C-T）配置相结合的系统。此设置满足了在指定范围内光谱分辨率的需要，而不会引入任何额外的像差 21 。

In this paper, two different spectrometer setups have been combined to record spectra in two different Raman ranges: 532 nm to 703 nm and 784.65 to 1100 nm. The developed spectrometer has two light entrance slits in two side-by-side arms. Light enters from each of these entrance slits and then passes into the corresponding C–T spectroscopic setup. After separating the wavelengths by a grating, the light is focused by the corresponding mirror onto a linear image sensor (CCD). Due to the importance of signal-to-noise ratio in Raman spectroscopy, there is no limit on cutting and reducing the dimensions of optical elements in the design. With suitable exposure dimensions, a sufficient signal to noise (SNR) ratio will be achieved.在本文中，两种不同的光谱仪设置组合记录光谱在两个不同的拉曼范围：532 nm至703 nm和784.65至1100 nm。开发的光谱仪在两个并排的臂上有两个光入口狭缝。光从每一个入口狭缝进入，然后进入相应的C-T光谱装置。通过光栅分离波长后，光通过相应的反射镜聚焦到线性图像传感器（CCD）上。由于信噪比在拉曼光谱中的重要性，在设计中对光学元件的切割和减小尺寸是没有限制的。通过适当的曝光尺寸，可以获得足够的信噪比。

Contrary to the problem and challenge in the design and optical adjustment of arrangements with moving elements, due to the independence of the two integrated spectrometers in Dual Spectrometer Single Detector (DSSD), there is no limitation in the adjustment of the optical arrangements. The optical adjustment of each spectrometer does not cause any disturbance to the adjustment of the other spectrometer. Each spectrometer is designed independently of each other so that the optical aberrations reach their minimum value and the maximum signal-to-noise is observed in the output.与移动元件布置设计和光学调整中存在的问题和挑战相反，由于双光谱仪单探测器（DSSD）中两台集成光谱仪的独立性，使得光学布置的调整不受限制。每台光谱仪的光学调整不会对其他光谱仪的调整造成任何干扰。每个光谱仪相互独立设计，使光学像差达到最小值，并在输出中观察到最大的信噪比。

The standard peaks of neon and mercury-argon lamps, as reported in the National Institute of Standards and Technology (NIST), are used for wavelength calibration22. The Raman spectra were recorded using both lasers by using the cyclohexane Raman standard sample23,24,25,26. The spectral resolution Full Width at Half Maximum (FWHM) is 0.17 nm for the 532 nm -setup and 0.44 nm for the 784 nm setup.根据美国国家标准与技术研究所（NIST）的报告，氖灯和汞氩灯的标准峰用于波长校准 22。采用环己烷拉曼标准样品 23,24,25,26 记录两种激光器的拉曼光谱。532 nm设置的光谱分辨率为0.17 nm， 784 nm设置的光谱分辨率为0.44 nm。

Method 方法

The correlation between the degree of coma aberration and the orientations of the optical components is used to optimize the optical setup27,28. In Fig. 1, the angles formed by the incident light beam striking the grating and the angles at which it disperses are illustrated.利用光学元件方向与彗差的相关性，优化光学设置 27,28。在图1中，说明了入射光束撞击光栅形成的角度及其散射的角度。

The optical path along the surface of the grating.沿着光栅表面的光路。

According to Eq. (1), these angles are related to the diffraction order and the density of the grating lines29.由式(1)可知，这些角度与衍射阶和光栅线密度 29 有关。

In this equation, λ represents the wavelength of the diffracted light. The angles of the incoming light and the diffracted light, denoted as θi and θd, correspond to their positions relative to the normal of the grating. Additionally, d indicates the width of the grooves, while m refers to the order of diffraction.在这个方程中，λ表示衍射光的波长。入射光与衍射光的角度分别表示为θ i 和θ d ，对应于它们相对于光栅法线的位置。d表示凹槽宽度，m表示衍射阶数。

The new method presented in accurate wavelength calibration method for compact CCD spectrometer has been used30. In this research, noise reduction is done with the binomial method peaks31. The Local Maximum Method is used to identify peaks, and a Gaussian function is then fitted to these peaks.在紧凑型CCD光谱仪精确波长定标方法中提出的新方法已被用于 30 。本研究采用二项法降噪，峰值 31 。局部最大值法用于识别峰值，然后将高斯函数拟合到这些峰值上。

In order to remove unwanted background fluorescence from a Raman spectrum, the second derivative method is utilized to establish a polynomial function that effectively reduces this interference. By implementing this approach, the background is effectively subtracted from the Raman spectrum, enabling more precise identification of Raman peaks.为了从拉曼光谱中去除不需要的背景荧光，二阶导数方法被用来建立一个多项式函数，有效地减少了这种干扰。通过实现这种方法，可以有效地从拉曼光谱中减去背景，从而更精确地识别拉曼峰。

The initial wavelength range of 784.56 nm on the active area of the detector matches perfectly with the final wavelength range of 532 nm arrangement. Therefore, the data obtained from the 784.65 nm setup is inversely related to that from the 532 nm setup. Consequently, when transitioning between these two setups to collect data, the spectrum is presented in a mirrored fashion.探测器有源区的初始波长范围为784.56 nm，与最终波长范围为532 nm的排列完全匹配。因此，从784.65 nm设置获得的数据与从532 nm设置获得的数据成反比。因此，当在这两种设置之间转换以收集数据时，频谱以镜像方式呈现。

Experimental configuration实验配置

The Schematic illustration of the dual laser Raman setup is shown in Fig. 2. In this setup, the Raman spectra produced by both lasers are collected into optical fibers. The Raman spectrum generated by the 532 nm laser is passed through the optical fiber and fed into the input Slit. Similarly, the Raman spectrum produced by the 784.65 nm laser is directed into the entrance slit port of its corresponding setup using another optical fiber. The lasers are individually activated, with only one laser directed towards the sample through the optical pathway at a time. The two C–T arrays are positioned symmetrically next to each other, with the detector placed directly in the center between them. The second mirror in each spectrometer is connected to a column holder to ensure that the central wavelength light focuses on the detector perpendicularly. By using vertically mounted mirrors on a column to concentrate the dispersed light from the gratings, the entire system was made more compact and efficient.双激光拉曼装置的示意图如图2所示。在这种设置中，两种激光器产生的拉曼光谱被收集到光纤中。532 nm激光产生的拉曼光谱通过光纤输入狭缝。同样，784.65 nm激光器产生的拉曼光谱通过另一根光纤进入相应装置的入口狭缝口。激光被单独激活，一次只有一个激光通过光路指向样品。两个C-T阵列彼此对称地相邻放置，探测器直接放置在它们之间的中心。每台光谱仪的第二面反射镜与柱架相连，以确保中心波长的光垂直聚焦在探测器上。通过在柱子上使用垂直安装的镜子来集中来自光栅的分散光，整个系统变得更加紧凑和高效。

On the left side of the image is a schematic representation of the Raman setup, and the schematic of the DSSD setup is shown on the right side.图像的左侧是拉曼设置的原理图，右侧是DSSD设置的原理图。The optical plane includes points such as the central points of the mirrors, the diffraction grating, the midpoint of the slit, and the horizontal line that intersects the midpoint of the detector and is parallel to its length. The optical plane is tilted by 10 degrees around the axis that passes through the center of the detector pixel array. Both configurations of the spectrometer have a 10-degree angle, with the angles facing in opposite directions. This modification was made without adjusting the angles of the optical components in the spectrometer’s optical plane or affecting the second set of mirrors. In Fig. 3, the angle between the horizontal plane and the optical plane is shown. When looking at the detector from the front, the wavefront of the light beam input setup emitting from entrance slit of 532 nm setup is oriented downward, while the light input setup from entrance slit of 784.65 nm setup is oriented upward. When the rotation angle reaches zero degrees, the optical plane aligns perfectly with the horizontal plane, making the spectrometer comparable to traditional spectrometers.

光学平面包括镜的中心点、衍射光栅、狭缝的中点以及与探测器的中点相交并与其长度平行的水平线等点。光学平面围绕穿过探测器像素阵列中心的轴倾斜10度。两种配置的光谱仪都有一个10度角，两个角朝向相反的方向。这种修改没有调整光谱仪光学平面上光学元件的角度，也没有影响第二组反射镜。在图3中，显示了水平面与光学平面之间的角度。从正面看探测器时，从532 nm设置的入口狭缝发射的光束输入装置的波前朝向向下，而从784.65 nm设置的入口狭缝发射的光束输入装置的波前朝向向上。当旋转角度达到零度时，光学平面与水平面完美对齐，使光谱仪与传统光谱仪相媲美。

The slit inputs in both Raman setups are 25 microns in size. Spherical mirrors with a diameter of 25 mm and a focal length of 100 mm are utilized. The gratings have a square shape measuring 25 × 25 mm. The Raman grating setups 532 nm and 784.65 nm have line densities of 1200 and 600 lines per millimeter, respectively. The Raman spectrum was recorded using the TCD1304DG sensor, known for its exceptional sensitivity and low dark current. This high-performance detector has 3648 pixels, each measuring 200 × 8 microns, arranged along a single dimension. The sensor can detect wavelengths from 400 nm to 1100 nm, covering the required range for dual laser Raman spectroscopy, specifically 532 nm to 708 nm and 784.65 nm to 1100 nm.两种拉曼装置的狭缝输入尺寸均为25微米。球面反射镜的直径为25毫米，焦距为100毫米。光栅有一个正方形的形状测量25 × 25毫米。拉曼光栅设置532 nm和784.65 nm，线密度分别为1200和600线/毫米。拉曼光谱是用TCD1304DG传感器记录的，以其卓越的灵敏度和低暗电流而闻名。这种高性能探测器有3648个像素，每个像素的尺寸为200 × 8微米，沿单一维度排列。该传感器可以检测400 nm至1100 nm的波长，覆盖双激光拉曼光谱所需的范围，特别是532 nm至708 nm和784.65 nm至1100 nm。

Associative angle between the horizontal plane and the optical plane in a DSSD configuration: (a) for the 532 nm arrangement and (b) for the 784.65 nm arrangement.DSSD配置中水平面与光平面的结合角：(a)为532 nm排列，(b)为784.65 nm排列。

Results and discussion 结果与讨论

An operational prototype of a spectrometer has successfully been constructed, with precise measurements of 180 mm in length, 180 mm in width, and 122 mm in height. The emission spectra of mercury-argon and neon lamps that emit standard radiation were recorded using two different setups. One end of the optical fiber was connected to the light source, while the other end was connected to the selected input slit during the measurement. In Fig. 4, the radiation spectrum of standard lamps and the Raman spectrum of the standard sample of cyclohexane are illustrated. These spectra have been refined using the binomial smoothing method to reduce noise. Additionally, to further reduce noise, each Raman spectrum has been averaged five times, and each radiation spectrum from the standard lamp has been averaged 100 times. A second derivative method has been used to accurately analyze the Raman spectrum, eliminating background spectrum during the fitting process.一个可操作的光谱仪原型已经成功构建，精确测量长180毫米，宽180毫米，高122毫米。使用两种不同的装置记录了汞氩灯和霓虹灯的发射光谱，这些灯发出标准辐射。测量时将光纤的一端连接到光源上，另一端连接到选定的输入狭缝上。图4给出了标准灯的辐射光谱和环己烷标准样品的拉曼光谱。利用二项平滑法对这些光谱进行了细化，以降低噪声。此外，为了进一步降低噪声，每个拉曼光谱被平均5次，每个标准灯的辐射光谱被平均100次。采用二阶导数法对拉曼光谱进行精确分析，消除了背景光谱。

The spectrum illustrated in the Fig. 4a from 532 nm setup revealed closely positioned mercury lines at 576.96 nm and 579.066 nm, as well as neon lines at 614.306 nm and 616.359 nm, which were distinctly separated without any overlapping. Additionally, upon closer analysis of the Raman spectrum of the cyclohexane standard sample using the 532 nm laser, distinct peaks were identified at 2923.8 and 2938.3 cm− 1. This Raman spectrum is shown in Fig. 4b. Similarly, as shown in Fig. 4c, the spectral lines recorded by the 784.65 nm setup, demonstrated the ability to distinguish closely located lines for neon and argon lamps at wavelengths of 841.843 nm, 840.82 nm, and 842.47 nm. Furthermore, the Raman spectrum of the cyclohexane sample, obtained using a 784.65 nm laser, exhibits peaks at 2923.8 cm⁻¹ and 2938.3 cm⁻¹, as illustrated in the spectrum shown in Fig. 4d.图4a所示的532 nm的光谱显示，576.96 nm和579.066 nm处的汞谱线和614.306 nm和616.359 nm处的氖谱线位置紧密，它们明显分开，没有重叠。此外，利用532 nm激光对环己烷标准样品的拉曼光谱进行了进一步分析，在2923.8和2938.3 cm − 1 处发现了明显的峰。拉曼光谱如图4b所示。同样，如图4c所示，784.65 nm装置记录的光谱线显示出能够区分波长为841.843 nm， 840.82 nm和842.47 nm的霓虹灯和氩灯的近距离线。此外，使用784.65 nm激光获得的环己烷样品的拉曼光谱显示出2923.8 cm⁻¹和2938.3 cm⁻¹的峰值，如图4所示。

(a) and (b) represent the radiation spectrum of standard lamps and the Raman spectrum obtained from a cyclohexane sample using a 532 nm setup. Similarly, the spectra recorded with the 784.65 nm configuration are included in the (c) and (d).(a)和(b)表示标准灯的辐射光谱和使用532 nm设置从环己烷样品中获得的拉曼光谱。同样，784.65 nm配置记录的光谱包括在(c)和(d)中。

To evaluate the effect of a 10-degree tilt in the optical plane on spectral resolution, we analyzed the experimental data collected from spectrometer and compared it with the theoretical predictions. The peaks in the experimental spectra were identified using the local maximum peaking method. Subsequently, these peaks were analyzed by fitting a Gaussian function to determine their widths. Our data analysis reveals an average resolution (FWHM) spectral width of 0.17 nm for the 532 nm configuration, and the 784.65 nm configuration yielded a width of 0.44 nm. The fitted Gaussian curves for the peaks corresponding to the neon and mercury lamps are illustrated in Fig. 5a and b, respectively. Notably, the peak for the neon lamp, located at a wavelength of 616.39 nm, represents the experimental outcome for the 532 nm setup, and the peak for the mercury lamp at 912.37 nm reflects the experimental result for the 784.65 nm setup.为了评估光学平面10度倾斜对光谱分辨率的影响，我们分析了从光谱仪收集的实验数据，并将其与理论预测进行了比较。用局部最大峰法对实验光谱中的峰进行了识别。随后，通过拟合高斯函数对这些峰进行分析以确定其宽度。我们的数据分析显示，532 nm配置的平均分辨率（FWHM）光谱宽度为0.17 nm， 784.65 nm配置的宽度为0.44 nm。霓虹灯和汞灯对应的峰的拟合高斯曲线分别如图5a和b所示。值得注意的是，霓虹灯的峰位于616.39 nm波长处，代表了532 nm设置的实验结果，汞灯的峰位于912.37 nm，反映了784.65 nm设置的实验结果。

(a) Fitting peak 616.39 nm of neon spectrum, (b) Fitting peak 912.3 nm of argon spectrum.(a)氖光谱616.39 nm拟合峰，(b)氩光谱912.3 nm拟合峰。

The determination of spectral resolution in a C–T spectrograph is conducted using (2). Initially, for theoretical calculations, it is assumed that the angle formed by the optical plane is zero. Subsequently, Eq. (2) is used to calculate the average spectral resolution across the entire spectral range32.C-T光谱仪光谱分辨率的确定使用(2)进行。首先，在理论计算中，假设光平面形成的角度为零。随后，利用式(2)计算整个光谱范围 32的平均光谱分辨率。

(2)

In this equation, M represents the tangential magnification of the entrance slit, which is determined by the focal length F2 of the second concave mirror, divided by the focal length F1 of the first concave mirror33. This relationship can be expressed mathematically as . Here,Ws denotes the width of the entrance slit and the term signifies the linear dispersion of the spectrometer. The process outlined in deriving Eq. (1) provides a method for calculating this value.

(3)

By substituting Eq. (3) into Eq. (2) and calculating using Eq. (1), the spectral resolution determines using Eq. (4).

将Eq.(3)代入Eq.(2)，利用Eq.(1)计算，光谱分辨率由Eq.(4)确定。(4)

According to the spectral resolution results presented in Table 1, creating a 10-degree angle for the optical plane has a negligible effect on the spectral resolution. Optical aberrations play a crucial role in degrading the spectral resolution of a spectrometer, leading to discrepancies between theoretical predictions and experimental measurements. Spherical mirrors inherently exhibit both spherical aberrations and astigmatism, which cannot be entirely eliminated; however, certain techniques can effectively reduce the impact of astigmatism28,34,35,36,37,38. Coma aberration, while somewhat manageable using Shaffer’s equation, can only be minimized at specific wavelengths, making it impossible to eliminate across the entire spectrum12,39,40.

According to the Lambert’s cosine law, the intensity level increased by a significant 10 degrees when taking into account the cosine coefficient41. This is approximately equivalent to 98.5% of the intensity level at a zero-degree angle.根据朗伯余弦定律，当考虑到余弦系数 41时，强度水平显著增加了10度。这大约相当于零度角时强度水平的98.5%。

The relation of wavelength in terms of pixel number, which is obtained by fitting a 3rd degree polynomial function on the standard atomic peaks, shows the relationship between each pixel of the detector and the wavelength. This is expressed as an Eq. (5).波长与像素数的关系通过对标准原子峰的三次多项式函数拟合得到，显示了探测器各像素数与波长的关系。这表示为Eq.(5)。

where P represent the pixel number, λ signify the wavelength associated with pixel P, C denote the wavelength for pixel 0. The factors C1, C2 and C3 correspond to the first, second and third coefficients, respectively, and are measured in units of (nm/pixel), (nm/pixel2) and (nm/pixel3). The results of the third-degree polynomial regression are presented in Table 2. The R-squared value of 1 for the 532 nm setup and the R-squared value of 0.999999 for the 784.65 nm setup demonstrate the remarkable accuracy of the calibration method used. Additionally, the standard errors associated with the derived coefficients for the polynomial function are 0.020038 for the 532 nm setup and 0.061712 for the 784.65 nm setup, respectively.式中，P表示像素数，λ表示像素数P对应的波长，C表示像素数0对应的波长。因子C 1 、C 2 和C 3 分别对应第一、二、三系数，单位为（nm/pixel）、（nm/pixel 2 ）和（nm/pixel 3 ）。三次多项式回归结果如表2所示。532 nm设置的r平方值为1,784.65 nm设置的r平方值为0.999999，表明所使用的校准方法具有显著的准确性。此外，与多项式函数的推导系数相关的标准误差分别为532 nm设置的0.020038和784.65 nm设置的0.061712。

To determine the intensity value of the Raman spectrum, we use the signal-to-noise ratio. The signal is represented by the height of the peak at 801 cm− 1 in the Raman spectrum of the cyclohexane sample. In contrast, the noise is quantified by measuring the standard deviation from the baseline in a region of the Raman spectrum where no peaks are present. The ratio of these two measurements from two distinct Raman spectra illustrates the SNR relationship42,43. Based on this analysis, it was found that the SNR ratio for the setup using the 532 nm laser is 7145, while the ratio for the arrangement with the 784.65 nm laser is 40.为了确定拉曼光谱的强度值，我们使用信噪比。信号表示为环己烷样品拉曼光谱中801 cm − 1 处的峰的高度。相反，噪声是通过测量拉曼光谱中没有峰值的区域的基线的标准偏差来量化的。两个不同的拉曼光谱的这两个测量值的比值说明信噪比关系 42,43。通过分析，发现532 nm激光器布置的信噪比为7145，而784.65 nm激光器布置的信噪比为40。

This unique setup can be used in both Fluorescence Correlation Spectroscopy (FCS) and Raman Correlation Spectroscopy (RCS) systems which can be considered in future researches44,45. Furthermore, using a two-dimensional detector enables the simultaneous record of four Raman spectra.这种独特的设置可以在荧光相关光谱（FCS）和拉曼相关光谱（RCS）系统中使用，可以在未来的研究中考虑 44,45。此外，使用二维探测器可以同时记录四个拉曼光谱。

Conclusion 结论

This paper describes the development of a spectrometer with two entrance slits for light, specifically designed for dual laser Raman spectroscopy device. The instrument uses two lasers with wavelengths of 532 nm and 784.65 nm, covering Raman shift ranges of 0 to 4686 cm− 1 and 0 to 4386 cm− 1, respectively. By incorporating a 10-degree angle in the optical setup, there is negligible impact on both the spectral resolution and intensity of the output spectrum. Switching between two selected modes for recording and displaying spectra is achieved in a fraction of a second. Importantly, the system does not have any optical moving parts, reducing the risk of wavelength errors during spectral measurements. With the dimensions of the optical components maintained, the spectrometer records a sufficient signal-to-noise ratio in the Raman spectrum. The average resolution (FWHM) of line spectra in the 532 nm Raman range is 0.17 nm (equivalent to 4.6 cm− 1), and the spectral resolution for the 784.65 nm Raman range is 0.44 nm (equivalent to 6.11 cm− 1). The integration time required for spectroscopy in this setup is 500 µs for both configurations.本文介绍了一种专门为双激光拉曼光谱装置设计的双入口光狭缝光谱仪的研制。该仪器采用波长为532 nm和784.65 nm的两种激光器，拉曼位移范围分别为0 ~ 4686 cm− 1和0 ~ 4386 cm− 1。通过在光学设置中加入10度角，对输出光谱的光谱分辨率和强度的影响可以忽略不计。用于记录和显示光谱的两种选择模式之间的切换在几分之一秒内实现。重要的是，该系统没有任何光学运动部件，减少了光谱测量期间波长误差的风险。在保持光学元件尺寸不变的情况下，光谱仪在拉曼光谱中记录了足够的信噪比。532 nm拉曼光谱谱线的平均分辨率（FWHM）为0.17 nm（相当于4.6 cm− 1）， 784.65 nm拉曼光谱谱线的平均分辨率为0.44 nm（相当于6.11 cm− 1）。在此设置中，两种配置所需的光谱积分时间为500µs。

Data availability 数据可用性

The datasets used and/or analysed during the current study available from the corresponding author on reasonable request.在当前研究中使用和/或分析的数据集可根据通讯作者的合理要求提供。

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