CN-117007532-B - Microscopic circular dichroism spectrum detection system based on single photon counting acquisition method

CN117007532BCN 117007532 BCN117007532 BCN 117007532BCN-117007532-B

Abstract

The invention relates to the field of optical detection of samples, in particular to a microscopic circular dichroism spectrum detection system based on a single photon counting acquisition method, which comprises a light source module, a polarizing module, an excitation module, a microscopic imaging module, a synchronization module, an acquisition module and a data processing module, wherein the light source module generates wide spectrum continuous light beams, the polarizing module polarizes the wide spectrum continuous light beams into periodically-changed left-handed and right-handed polarized light, the periodically-changed left-handed and right-handed polarized light in the excitation module interacts, the acquisition module obtains interacted light intensity signals, the data processing module mathematically converts the light intensity signals into corresponding circular dichroism spectrum information, the synchronization module provides control and acquisition time sequence information in the whole circular dichroism spectrum acquisition process, and the microscopic imaging module can perform microscopic imaging on a measured sample and select interaction positions before circular dichroism spectrum acquisition.

Inventors

SUI LAIZHI
ZHANG YUTONG
NIU GUANGMING
JIANG JUTAO
YUAN KAIJUN

Assignees

中国科学院大连化学物理研究所

Dates

Publication Date: 20260512
Application Date: 20220427

Claims (6)

1. The microscopic circular dichroism spectrum detection system based on the single photon counting acquisition method is characterized by comprising a light source module, a polarization module, an excitation module, an acquisition module, a data processing module, a microscopic imaging module, a synchronization module and a white light source (14) which are sequentially arranged in a line; the data processing module is respectively connected with the acquisition module and the synchronization module through data transmission lines, the synchronization module is connected with the polarization module through data transmission lines, the microscopic imaging module is arranged on a refraction light path of the excitation module, and the white light source (14) is arranged on a reflection light path of the excitation module; the light source module comprises a wide-spectrum continuous light source (1), a first reflecting mirror (2) and a second reflecting mirror (3) which are sequentially arranged on the light path of the light source module; The polarizing module comprises a polaroid (4) and a photoelastic modulator (5) which are sequentially arranged in a line, the polaroid (4) and the second reflecting mirror (3) are arranged in a line, and the synchronous module is connected with the photoelastic modulator (5) through a data transmission line; The acquisition module comprises a first focusing mirror (11) and a grating beam splitter (12) which are sequentially arranged in a line, and further comprises a photomultiplier (13), wherein the first focusing mirror (11) and the movable reflecting mirror (10) are arranged in a line, the photomultiplier (13) is arranged on a reflection light path of the grating beam splitter (12), and the photomultiplier (13) is connected with the data processing module through a data transmission line.
2. The microscopic circular dichroism spectrum detection system based on the single photon counting collection method according to claim 1, wherein the excitation module comprises a movable beam splitting sheet (6), a first reflective objective lens (7), a second reflective objective lens (9) and a movable reflector (10) which are sequentially arranged in a line, the movable beam splitting sheet (6) is arranged in a line with the photoelastic modulator (5), the microscopic imaging module is arranged on a refraction light path of the movable beam splitting sheet (6), the white light source (14) is arranged on a reflection light path of the movable reflector (10), and a sample area for placing a tested sample (8) is arranged between the first reflective objective lens (7) and the second reflective objective lens (9).
3. The microscopic circular dichroism spectrum detection system based on the single photon counting acquisition method according to claim 1, wherein the data processing module comprises a single photon counting acquisition card (18) and a data processing computer (19), and the single photon counting acquisition card (18) is respectively connected with the synchronization module, the data processing computer (19) and the photomultiplier (13) through data transmission lines.
4. The microscopic circular dichroism spectrum detection system based on the single photon counting acquisition method according to claim 1, wherein the microscopic imaging module comprises a focusing mirror II (15) and a CCD camera (16) which are sequentially arranged on a refraction light path of the movable beam splitting sheet (6), and further comprises an imaging display (20) connected with the CCD camera (16) through a data connecting line.
5. The microscopic circular dichroism spectrum detection system based on the single photon counting acquisition method according to claim 1, wherein the synchronization module comprises a synchronization controller (17), and the synchronization controller (17) is respectively connected with the photoelastic modulator (5) and the single photon counting acquisition card (18) through data connection lines.
6. The microscopic circular dichroism spectrum detection method based on the single photon counting acquisition method is applied to the microscopic circular dichroism spectrum detection system based on the single photon counting acquisition method as claimed in claim 2, and is characterized by comprising the following steps: When the spectrum measurement is carried out on the measured sample, the movable beam splitting sheet (6) and the movable reflecting mirror (10) in the excitation module are arranged in a line, and white light emitted by the white light source (14) sequentially passes through the movable reflecting mirror (10) and the second reflecting objective lens (9) in the excitation module to illuminate the sample area of the measured sample (8), so that the sample area of the measured sample (8) sequentially passes through the first reflecting objective lens (7) and the movable beam splitting sheet (6) and then is imaged in the microscopic imaging module; When the spectrum collection is carried out on the tested sample, the movable beam splitting sheet (6) and the movable reflecting mirror (10) in the excitation module are all arranged in a line, the wide spectrum light beams emitted by the wide spectrum continuous light source (1) in the light source module sequentially pass through the polarizing module, the first reflecting objective lens (7) in the excitation module and the sample area of the tested sample (8), and the transmitted light sequentially passes through the second reflecting objective lens (9) and the collection module and then carries out the spectrum collection on the tested sample (8) in the data processing module.

Description

Microscopic circular dichroism spectrum detection system based on single photon counting acquisition method Technical Field The invention relates to the field of optical detection of samples, in particular to a microscopic circular dichroism spectrum detection system based on a single photon counting acquisition method. Background Circular dichroism spectrum is an optical spectrum in which asymmetric molecular configuration and conformation are inferred, and absorption coefficients of an optically active substance for left-handed and right-handed polarized light constituting plane polarized light are unequal, that isTaking the spectrum of the plane polarized light as an abscissa and taking the difference of the absorptivity as the difference) The spectrum obtained by taking the ordinate is the circular dichroism spectrum of the optical active substance, the difference of the absorptivity can be obtained by obtaining and calculating the light intensity of the left-hand polarized light and the right-hand polarized light which are transmitted through the optical active substance to be measured, and therefore, the main task of the circular dichroism spectrum measuring system is to measure the light intensity of the left-hand polarized light and the right-hand polarized light which are transmitted through the optical active substance to be measured. In the presently reported results, the measurement of the light intensity of the left-hand and right-hand polarized light transmitted through the measured photoactive material is completed by adopting a modulation method, the method superimposes the periodic modulation signals consistent with the variation period of the left-hand and right-hand polarized light on the light intensity signals collected by the photodiodes, and the method distinguishes the left-hand and right-hand polarized light components of the light intensity signals collected by the photomultiplier in one period, so that the signals must be modulated and demodulated in the process of obtaining the left-hand and right-hand polarized light transmitted through the measured photoactive material, and the process has higher requirements on the sensitivity and the time accuracy of related instruments and can noise of a signal superimposing system. Disclosure of Invention In order to solve the problem, the invention creatively adopts a single photon counting method to realize detection of the left-handed polarized light and the right-handed polarized light transmitted through the tested photoactive material, and by adopting the method, the light intensity can be directly converted into a digital signal, and the digital signal can be directly subjected to digital calculation to obtain the corresponding circular dichroism spectrum. In order to meet the detection of circular dichroism spectrum of micro-area samples and samples with uneven surface distribution, the invention is provided with a microscopic imaging module at the same time, so that the system can meet the measurement of micro-area and selected area. The invention aims to provide a microscopic circular dichroism spectrum detection system based on a single photon counting acquisition method, which utilizes microscopic imaging to realize microscopic imaging and focusing of a sample before measurement and can realize detection of micro-area or selected area circular dichroism of the measured sample. The technical scheme adopted by the invention for achieving the purpose is as follows: the microscopic circular dichroism spectrum detection system based on the single photon counting acquisition method comprises a light source module, a polarizing module, an excitation module, an acquisition module, a data processing module, a microscopic imaging module, a synchronization module and a white light source which are sequentially arranged in a line; The data processing module is respectively connected with the acquisition module and the synchronization module through data transmission lines, the synchronization module is connected with the polarization module through data transmission lines, the microscopic imaging module is arranged on a refraction light path of the excitation module, and the white light source is arranged on a reflection light path of the excitation module. The light source module comprises a wide-spectrum continuous light source and a first reflecting mirror and a second reflecting mirror which are sequentially arranged on the light path of the wide-spectrum continuous light source. The polarizing module comprises a polaroid and a photoelastic modulator which are sequentially arranged in a line, the polaroid and the reflecting mirror are arranged in a line, and the synchronous module is connected with the photoelastic modulator through a data transmission line. The excitation module comprises a movable beam splitting sheet, a first reflective objective, a second reflective objective and a movable reflector which are arranged in a line in s