CN101598597B - Device for detecting intensity distribution of polarized components in different directions - Google Patents

Abstract

The invention is a detection device for the light intensity distribution of polarization components in different directions, which consists of a light source, a polarization state adjustment device, a spectral beam splitter, an optical focusing component, a photoelectric imaging device, a lower light-transmitting film, an upper light-transmitting film, a fluorescent molecular layer, Composed of nano-scanning components, fiber optic probes, and photoelectric sensors; the output beam of the light source is focused to the fluorescent molecular area through the polarization state adjuster, spectral beam splitter and optical focusing components in sequence. The fluorescent molecular area consists of an upper light-transmitting film, a fluorescent molecular layer, and a lower transparent Composed of optical film, a fiber optic probe is placed above the fluorescent molecular area. One end of the optical fiber probe near the fluorescent molecular area is connected to the nano-scanning component, and the other end is connected to the photoelectric sensor. The optical fiber probe can detect the fluorescent light of the polarization component of the fluorescent molecular layer in different directions. Intensity distribution, so as to obtain the light intensity distribution of polarization components in different directions in the light field. The invention has the characteristics of high detection resolution, simple system configuration, and can realize light intensity detection in different polarization directions.

Description

A detection device for light intensity distribution of polarization components in different directions

technical field

The invention belongs to the technical field of applied optics, and relates to a light intensity distribution detection device, in particular to a detection device for the light intensity distribution of polarization components in different directions. It is mainly used in the fields of near-field optics, optical storage, lithography, optical microscopy, optical micromachining and micromanipulation.

Background technique

Light intensity distribution characteristics play a very important role in optical systems, and the study of light intensity distribution characteristics, as the core link in the design and research process of optical and optoelectronic systems, has received extensive attention. For example, in an optical storage system, the light intensity distribution in the focus area is directly related to the information storage density, and the lateral spot size determines the size of the optical information point, which determines the information storage density; The large size can reduce the difficulty of realizing the servo system in the optical storage system. In the field of optical micromanipulation, the tiny particles in the light field are affected by the light gradient force and light scattering force, and the light intensity distribution of the light field directly determines the distribution of the light gradient force and light scattering force, so it is very important to analyze and detect the light intensity distribution characteristics . The beam has vector characteristics, and the propagation, focusing, and photoelectric conversion effects of different polarization beams are different. For example, after the azimuth polarized beam is focused by the lens, the focal spot is not the usual circular spot shape, but a circular focal spot. Therefore, the detection of light intensity distribution of polarization components in different directions has important research significance and wide application value, and plays a very important role in the fields of near-field optics, optical storage, lithography technology, optical microscopy technology, optical micromachining and micromanipulation. important role. In the prior art, there are several light intensity distribution detection technologies, including photoelectric imaging method, knife-edge method (refer to the paper "A new understanding of the measurement of Gaussian beam spot size by the knife-edge method," "Laser and Infrared", Volume 32, Issue 3) and The near-field optical method (refer to the method for detecting the small spot of the objective lens of the invention patent, patent number: ZL00127831.2) has considerable advantages. However, there are essential deficiencies: 1) The photoelectric imaging method and the knife-edge method use two micro-photoelectric devices and the knife-edge method for detection respectively, and the resolution of light intensity detection is low; 2) The near-field optical method is based on a near-field optical microscope and uses a fiber optic probe to directly collect Light field and near-field light energy, the system structure is complex; 3) The existing photoelectric imaging method, knife-edge method and near-field optical method all have an essential deficiency: because they cannot distinguish the polarization characteristics of the collected light field, it is impossible to achieve polarization components in different directions. Detection of strong distributions.

Contents of the invention

In order to solve the above-mentioned problems in the prior art, the present invention provides a detection device for the distribution of light intensity of polarization components in different directions, which has the characteristics of high detection resolution, simple system structure, convenient use, and can realize light intensity detection in different polarization directions.

The basic idea of the present invention is: the light beam is focused by an optical focusing component to form a measured light field area, and the upper and lower planes are light-transmitting films in the measured light field area, and a fluorescent molecular layer is arranged between the two light-transmitting films; the fluorescent molecular layer Fluorescent molecules in different polarization states have different fluorescence rates to light fields of different polarization states. Fluorescent molecular layers distributed in different polarization directions can produce fluorescence of polarized light in the corresponding direction. Fiber optic probes are used to detect the fluorescent light field distribution of the fluorescent molecular layer, namely The light intensity distribution information of polarization components in different directions can be obtained.

The technical solution adopted by the present invention to solve the above technical problems is: a detection device for the light intensity distribution of polarization components in different directions, which consists of a light source, a polarization state adjustment device, a spectral beam splitter, an optical focusing component, a photoelectric imaging device, and a lower light-transmitting film , upper light-transmitting film, fluorescent molecular layer, nano-scanning components, fiber optic probes, and photoelectric sensors. A polarization adjustment device and a spectral beamsplitter are sequentially arranged on the optical path of the light source output beam, and an optical focusing component, a lower light-transmitting film, a fluorescent molecular layer, and an upper light-transmitting film are sequentially arranged in the direction of the reflected light path where the light source output beam is reflected by the spectral beam splitter The included angles between the lower light-transmitting film, the fluorescent molecular layer, the upper light-transmitting film and the propagation direction of the beam reflected by the spectral beamsplitter are all 70° to 90°; Photoelectric imaging device; the light emitted by the light source is reflected by the spectral beam splitter and the reflected light is focused by the optical focusing component to form the detected light field area. A fluorescent molecular layer is arranged between the two films of the lower transparent film and the upper transparent film, and the fluorescent molecules The layer is located in the focus of the optical focusing component to be detected in the light field area; the other side of the upper light-transmitting film is provided with a fiber optic probe, and one end of the fiber probe near the upper light-transmitting film is connected to the nano-scanning component, and the other end of the fiber probe is Connect with photoelectric sensor.

The light source is one of a gas laser, a solid laser, and an incoherent light source.

The polarization state adjusting device is one of wave plate type polarization state adjuster, liquid crystal polarization state adjuster and micro grating polarization state adjuster.

The optical focusing component is one of an achromatic microscope objective lens and a plan-field microscope objective lens.

The photoelectric imaging device is one of an area charge-coupled device imager and a complementary metal oxide semiconductor imager. The fluorescent molecular layer is one of an inorganic fluorescent molecular layer and an organic fluorescent molecular layer.

The nano-scanning component is one of a piezoelectric ceramic nano-scanner and a piezoelectric crystal nano-scanner.

The photoelectric sensor is a photodiode.

The working process of the present invention is as follows: the light beam emitted by the light source is adjusted by the polarization state adjuster and then directed to the spectrum beam splitter; Both the molecular layer and the upper light-transmitting film are located in the area of the detected light field formed by the focusing of the optical focusing components; the fluorescent molecules in the fluorescent molecular layer have different fluorescence rates for different polarization states of the light field, and the fluorescent molecular layers distributed in different polarization directions are It can generate fluorescence of polarized light in the corresponding direction. The fiber optic probe installed above the light-transmitting film detects the fluorescence intensity of the fluorescent molecular layer, and the photoelectric sensor connected to the other end of the fiber probe realizes photoelectric conversion; the nano-scanning component drives the fiber probe Scanning is performed to obtain the fluorescence light field distribution of fluorescent molecules distributed in different polarization directions. The fluorescence of fluorescent molecules distributed in different polarization directions corresponds to the measured polarized light in the corresponding direction, and the measurement of the light intensity distribution of polarization components in different directions is realized. The spectroscopic surface of the spectrum beam splitter has a reflectivity of more than 75% for the outgoing beam of the light source, and a transmittance of more than 70% for the fluorescence emitted by the fluorescent molecular layer. Therefore, in the process of measuring the intensity distribution of polarization components in different directions, the fluorescent molecular layer The emitted fluorescence sequentially passes through the lower light-transmitting film, the optical focusing component and the spectral beam splitter, and is imaged by the photoelectric imaging device, realizing the observation and monitoring of the measurement process.

The moving parts and their control in the device of the invention, as well as the photoelectric detection signal processing are all mature technologies. The inventive point of the present invention is to provide an optical path structure of a device for detecting the distribution of light intensity of polarization components in different directions.

Advantage and beneficial effect that the present invention has relative to prior art are:

1) The optical fiber probe is used to detect the fluorescence light field distribution of fluorescent molecules. Since fluorescent molecules with different polarization directions correspond to different polarization directions of the detected light field, and the fluorescence efficiency of fluorescent molecules is related to the intensity of the measured light field, the detection is different. The light intensity distribution of the polarization components in different directions can be obtained by the fluorescence light field distribution of the fluorescent molecules in the polarization direction. The present invention essentially overcomes the essential shortcomings of the prior art and can realize the detection of the light intensity distribution of the polarization components in different directions.

2) The optical fiber probe is used to detect the distribution of the fluorescent light field of the fluorescent molecules, which fully utilizes the high-resolution characteristics of near-field optics, so that the present invention has the characteristics of high detection resolution.

3) The photoelectric imaging device is coupled into the light beam by using a spectral beam splitter, so that the measurement process can be monitored, and it is easy to use and operate, easy to realize automation, and the whole system is simple in structure.

4) The use of the spectral beam splitter improves the utilization rate of the emitted light of the light source.

Description of drawings

Fig. 1 is a schematic diagram of the system structure of an embodiment of the present invention;

Detailed ways

The present invention will be further described in detail below in conjunction with the accompanying drawings. The following embodiments are better application forms of the present invention, but the following embodiments should not be regarded as a limitation of the present invention.

Example

The following part of this embodiment describes a detection device for the light intensity distribution of polarization components in different directions:

As shown in Figure 1, the detection device for realizing the distribution of polarized light intensity in different directions of the present invention includes a light source 1, a polarization state adjustment device 2, a spectral beam splitter 10, an optical focusing component 3, an electro-optical imaging device 11, and a lower light-transmitting film 9 , upper light-transmitting film 8, fluorescent molecular layer 4, nano-scanning component 5, optical fiber probe 6, photoelectric sensor 7. A polarization adjustment device 2 and a spectral beamsplitter 10 are sequentially arranged on the optical path of the light beam emitted by the light source 1, and an optical focusing component 3, a lower light-transmitting film 9, and a fluorescent The molecular layer 4, the upper light-transmitting film 8; the lower light-transmitting film 9, the fluorescent molecular layer 4, the upper light-transmitting film 8 and the spectrum beam splitter 10 reflect the beam propagation direction at an angle of 70° to 90°; the light beam emitted by the light source 1 is A photoelectric imaging device 11 is arranged on the reverse extension line of the reflected light path reflected by the spectral beamsplitter 10; the light emitted by the light source 1 is reflected by the spectral beamsplitter 10, and the reflected light is focused by the optical focusing component 3 to form the detected light field area, and the lower light-transmitting film A fluorescent molecular layer 4 is arranged between the two films of 9 and the upper light-transmitting film 8, and the fluorescent molecular layer 4 is located in the focal area of the optical focusing component 3, that is, the detected light field area. The other side of the upper light-transmitting film 8 is provided with a fiber probe 6 , one end of the fiber probe 6 close to the upper light-transmitting film 8 is connected to the nano-scanning component 5 , and the other end of the fiber probe 6 is connected to the photoelectric sensor 7 .

In the present invention, the light source 1 is a gas laser, adopts a helium-neon laser, and has a wavelength of 632.8 nanometers; the polarization adjustment device 2 is a wave plate type polarization adjustment device; the optical focusing component 3 is an achromatic microscopic objective lens; the photoelectric imaging device 11 is an area array A charge-coupled device imager; the fluorescent molecular layer 4 is a dye molecular layer; the nano-scanning component 5 is a piezoelectric ceramic nano-scanner; the photoelectric sensor 7 is a photomultiplier tube. The included angles between the lower light-transmitting film 9 , the fluorescent molecular layer 4 , the upper light-transmitting film 8 and the beam splitter 10 are all 90°.

The working process of the present invention is as follows: the light beam emitted by the light source 1 is regulated by the polarization state adjuster 2 and directed to the spectroscopic beam splitter 10; the emitted light beam of the light source 1 is reflected by the spectroscopic beam splitter 10 and then focused by the optical focusing component 3 to form a detected light field area; The lower light-transmitting film 9, the fluorescent molecular layer 4, and the upper light-transmitting film 8 are all located in the region of the detected light field formed by the optical focusing component 3 after focusing; the fluorescent molecules in the fluorescent molecular layer 4 have different fluorescence rates for light fields of different polarization states The fluorescent molecular layer 4 distributed in different polarization directions can produce the fluorescence of the polarized light in the corresponding direction, and the optical fiber probe 6 arranged above the light-transmitting film 8 detects the fluorescent light intensity of the fluorescent molecular layer 4, and is connected with the optical fiber probe 6 The photoelectric sensor 7 realizes photoelectric conversion; the nano-scanning part 5 drives the fiber optic probe 6 to scan to obtain the fluorescence light field distribution of fluorescent molecules distributed in different polarization directions, and the fluorescence of fluorescent molecules distributed in different polarization directions and the measured polarized light in the corresponding direction Correspondingly, the measurement of the light intensity distribution of polarization components in different directions is realized. The spectroscopic surface of the spectrum beam splitter 10 has a reflectivity greater than 75% for the light beam emitted by the light source 1, and a transmittance greater than 70% for the fluorescence emitted by the fluorescent molecular layer 4. Therefore, in the process of measuring the light intensity distribution of polarization components in different directions, the fluorescence The fluorescence emitted by the molecular layer 4 passes through the lower light-transmitting film 9 , the optical focusing component 3 and the spectral beam splitter 10 in sequence, and is received and imaged by the photoelectric imaging device 11 , realizing the monitoring of the measurement process.

The key of the present invention is that the distribution information of the detected fluorescent light field is used to detect the distribution information of the polarized light intensity, which has the characteristics of high detection resolution, simple system structure, convenient use, and can realize the detection of light intensity in different polarization directions. All similar structures, methods and similar changes of the present invention should be included in the protection scope of the present invention.

Claims (8)

1. A detection device for the light intensity distribution of polarization components in different directions, consisting of a light source, a polarization state adjustment device, a spectral beam splitter, an optical focusing component, a photoelectric imaging device, a lower light-transmitting film, an upper light-transmitting film, a fluorescent molecular layer, a nanometer Composed of scanning components, fiber optic probes, and photoelectric sensors, it is characterized in that: polarization state adjustment devices and spectral beamsplitters are arranged in sequence on the optical path of the light beam emitted by the light source, and optical The focusing part, the lower light-transmitting film, the fluorescent molecular layer, and the upper light-transmitting film; the included angles between the lower light-transmitting film, the fluorescent molecular layer, the upper light-transmitting film and the propagation direction of the reflected beam of the spectrum beam splitter are all 70° to 90°; A photoelectric imaging device is arranged on the reverse extension line of the reflected light path where the light source output beam is reflected by the spectral beam splitter; the reflected light reflected by the light source output beam by the spectral beam splitter is focused by an optical focusing component to form a detected light field area, and the lower light-transmitting film and A fluorescent molecular layer is set between the two films of the upper light-transmitting film, and the fluorescent molecular layer is located in the focal area of the optical focusing component, that is, the detected light field area; one side of the upper light-transmitting film corresponds to the fluorescent molecular layer, and the other side is set There is an optical fiber probe, one end of the optical fiber probe close to the upper light-transmitting film is connected with the nano-scanning component, and the other end of the optical fiber probe is connected with the photoelectric sensor. 2 . The detection device for light intensity distribution of polarization components in different directions according to claim 1 , wherein the light source is one of a gas laser, a solid-state laser, and an incoherent light source. 3 . 3. A detection device for light intensity distribution of polarization components in different directions according to claim 1, characterized in that: said polarization adjustment device is a wave plate type polarization adjustment device, a liquid crystal polarization adjustment device, a micro-grating A type of polarization adjuster. 4 . The detection device for light intensity distribution of polarization components in different directions according to claim 1 , wherein the optical focusing component is one of an achromatic microscope objective and a plan microscope objective. 5. The detection device of a kind of light intensity distribution of polarization components in different directions according to claim 1, characterized in that: the photoelectric imaging device is an area charge-coupled device imager, a complementary metal oxide semiconductor imager kind. 6 . The detection device for light intensity distribution of polarization components in different directions according to claim 1 , wherein the fluorescent molecular layer is one of an inorganic fluorescent molecular layer and an organic fluorescent molecular layer. 7 . The detection device for light intensity distribution of polarization components in different directions according to claim 1 , wherein the nano-scanning component is one of a piezoelectric ceramic nanoscanner and a piezoelectric crystal nanoscanner. 8 . The detection device for light intensity distribution of polarization components in different directions according to claim 1 , wherein the photoelectric sensor is a photodiode.

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