JP3905229B2 - Multi-directional simultaneous detection light concentrator and scanning near-field microscope - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention provides a light condensing system and a scanning system used in a scanning near-field microscope for the purpose of observing the shape of a solid surface in the nanometer region and measuring optical properties by irradiating or exciting the surface of the object to be measured. The present invention relates to a mold near-field microscope.
[0002]
[Prior art]
There are scanning near-field microscopes that detect light with a large solid angle using a lens optical system, such as an objective lens or a Cassegrain type objective lens. A scanning near-field microscope is a method of forming an image by scanning an optical probe on the surface of an object. The optical resolution is determined by the size of the bright spot of the light. The efficiency is increased by using a method that collects light at a solid angle. It is also possible to obtain an optical image depending on the angle by changing the direction in which the objective lens is placed.
[0003]
[Problems to be solved by the invention]
However, even though conventional optical detection methods and scanning optical probe microscopes can observe an optical image with high resolution for the time being, it is difficult to fully understand the information contained in the optical image. In other words, for the sake of simplicity, taking an optical microscope as an example, some images obtained with an optical microscope may become an image due to the unevenness of the object being bright and dark. If there is something that causes light brightness and darkness, such as light that becomes a dark and bright image by passing a filter through the detection light due to the fluorescent substance in the object, it will be separated It appears as an image that has some form. In the world of fluorescence microscopes, differential interference methods and fluorescence methods have been developed to separate them or make them stand out. The same is true for scanning optical probe microscopes that image the same light. It is important to know what the cause is as a result of observing the object, and develop a method to separate information from the signal. There is a need to.
[0004]
In a scanning near-field microscope that observes a minute region with nanometer resolution, the problem is more complicated because the shape of the object surface affects the optical image in addition to these. It is also possible to obtain an optical image depending on the angle by changing the direction in which the objective lens is placed, but in the method of obtaining the optical image depending on the angle by performing the same operation multiple times, the problem of reproducibility of the scanning position, There is a problem of the change of the object, and it is necessary to observe at the same time.
[0005]
[Means for Solving the Problems]
According to the multi-directional simultaneous detection light concentrator of the present invention, since the object is simultaneously detected by a plurality of optical waveguides or detectors, the problem of reproducibility of the scanning position and the problem of change of the object are solved. The It can be installed on both the transmission side and the reflection side, and can be used as a light detection method using conventional optical systems by integrating the individual signals obtained, and each signal is processed and imaged By doing so, it is possible to separate information derived from the surface shape of the object, the difference in material, etc., and observe the true physical properties of the object.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
[Embodiment 1]
FIG. 1A shows a view of a multidirectional simultaneous detection light concentrator according to Embodiment 1 of the present invention as seen from above. A waveguide hole 2 is formed so as to go to the center of the dome 1. An optical fiber having a flat end face is inserted into the waveguide hole 2. Photodetectors are optically connected to opposite ends of the optical fiber. Fixed optical probe to the center of the dome to the scanning near-field microscope housing by the mounting jig 3 is Sette Ingu to come. The optical probe is not an optical lever method, but controls the distance to the object by a self-detection method using a crystal resonator. Unlike the optical lever method, this method is easy to handle because it does not require an operation such as focusing a detection laser on the optical probe. In this model, 13 waveguide holes 2 are provided, and at the same time, light can be detected from 13 directions and each can be imaged. By integrating these simultaneously detected light signals, a light signal with a large solid angle is acquired, and can be used to increase the detection sensitivity of weak light signals. This method is more efficient and compact than an optical concentrator using a conventional lens optical system.
[0007]
FIG. 1B is a view of the multidirectional simultaneous detection light concentrator as seen from the bottom. The dome inner side 4 has a radius of 4 mm, and 13 optical fiber end faces having a diameter of 2 mm are arranged in a ¼ spherical surface shown in the figure.
As a result, unlike conventional ones, optical images with different angles can be observed simultaneously. If a spectroscope is optically connected to the opposite end of the optical fiber and the light is detected, it is possible to simultaneously measure the spectrum depending on the angle. If the multi-directional simultaneous detection light concentrator is placed on the upper surface of the sample, an angle-dependent light image in the reflection optical system of an opaque object can be observed.
[Embodiment 2]
FIG. 2 (A) shows a multi-directional simultaneous detection light concentrator according to Embodiment 2 of the present invention as seen from above. As in FIG. 1, the waveguide hole 2 is formed so as to go to the center of the dome 1, but the waveguide hole 2 exists only at an angle close to the horizontal with respect to the bright spot. The other configuration is basically the same as that shown in FIG. The difference from FIG. 1 is that the optical lever system can also be used to control the distance between the optical probe and the object. By using the optical lever method, the object in the solution can be observed. In addition, it is possible to control the distance between the optical probe and the object by using the contact mode method that scans the optical probe while keeping it in contact with the object. Things will be possible. When a multidirectional simultaneous detection light concentrator is installed on the upper side (reflection side) of an object and an optical image is observed, light is projected at an angle close to perpendicular to the bright spot due to the shadow of the optical probe itself. Since it is known that the angle does not come, the merit of adopting the optical lever method is given priority without providing an angle close to vertical. Of course, a self-detection method using a crystal resonator may be used.
FIG. 2B is a view of the multidirectional simultaneous detection light concentrator as seen from the bottom. The inside of the dome 4 has a radius of 5 mm, and an optical fiber having a flat end face opened into the waveguide hole 2 is inserted. Twenty-six optical fiber end faces with a diameter of 1 mm are arranged in two rows in an array. As a result, unlike conventional ones, optical images with different angles can be observed simultaneously. If a spectroscope is optically connected to the opposite end of the optical fiber to detect light, simultaneous measurement of the spectrum depending on the angle can be performed.
[Embodiment 3]
FIG. 3 shows a block diagram of a scanning near-field microscope equipped with a multidirectional simultaneous detection light concentrator 14 according to Embodiment 3 of the present invention. The multi-directional simultaneous detection light concentrator obtained by cutting out the upper part of the dome shown in the second embodiment in FIG. 2 is used as a reflection optical system. A saddle-like optical probe 5 is placed on a bimorph 6 that is a vibrating means, and the tip of the saddle-like optical probe 5 is vibrated perpendicularly to the object 7 so that the tip of the optical probe 5 and the surface of the object 7 The interatomic force acting on the substrate or other interaction-related force is detected by the displacement detection means 8 as a change in the vibration characteristics of the optical probe 5, and the distance between the tip of the bowl-shaped optical probe 5 and the surface of the object 7 is constant. The surface shape is measured by scanning the object 7 with the XYZ moving mechanism 10 while being controlled by the controller 9 so as to keep the surface shape. By guiding light from the external laser 13 to the bowl-shaped optical probe 5, the object 7 can be irradiated with light from the opening 11. An optical fiber 15 is inserted into the multidirectional simultaneous detection light collector 14, and the optical characteristics of the minute region are simultaneously measured by guiding and detecting the light acting on the object 7 to the optical characteristic measurement light detection means 12. be able to. Although only two optical fibers 15 are depicted in the figure, there are actually 26, and signals detected from different angles and directions are processed by the controller 9 to obtain information depending on the surface irregularities of the object 7, Information that depends on the material can be separated.
Although FIG. 3 shows a reflection type configuration in which the measurement light is detected on the reflection surface of the sample 7, a transmission type configuration in which the measurement light is detected on the transmission side is also possible. In general, an optical lever is used as the displacement detection means 8, but the displacement detection means 8 is not necessary by using an optical probe having a piezoelectric body.
[0008]
3 shows an apparatus configuration for vibrating the bowl-shaped optical probe 5. However, it is also possible to perform measurement as a contact mode AFM by using an apparatus configuration that does not vibrate the bimorph 6 or does not use the bimorph 6. . It is also possible to observe friction information that cannot be obtained by a method that does not vibrate.
Further, in these apparatuses, measurement in the liquid can be performed by providing a reservoir cover so that the probe and the sample are held in the liquid.
[0009]
【The invention's effect】
The present invention is implemented in the form as described above, and has the following effects.
By using a multi-directional simultaneous detection light concentrator for a scanning near-field microscope, it is possible to simultaneously detect light emitted from the optical probe and light generated as a result of the action of the object surface from any solid angle. . Using the obtained optical signals in an integrated manner improves the light collecting system using a conventional lens system in terms of the efficiency of detecting weak light. In addition, the design is easy and compact. When the obtained optical signals are separately imaged, simultaneous optical imaging from multiple directions can be performed. When imaging is performed by processing each signal, it is possible to separate and display a light image that does not depend on surface unevenness information and surface material information included in the signal.
[Brief description of the drawings]
FIG. 1 is a diagram showing a multidirectional simultaneous detection light concentrator according to a first embodiment of the present invention.
FIG. 2 is a diagram showing a multidirectional simultaneous detection light concentrator according to a second embodiment of the present invention.
FIG. 3 is a configuration diagram showing a scanning probe microscope equipped with a multidirectional simultaneous detection light concentrator according to a third embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Dome 2 ... Waveguide hole 3 ... Mounting jig 4 ... Dome inner side 5 ... Sponge-shaped optical probe 6 ... Bimorph 7 ... Object 8 ... Displacement detection Means 9 ... Controller 10 ... XYZ moving mechanism 11 ... Aperture 12 ... Optical characteristic measurement light detection means 13 ... Laser 14 ... Multi-directional simultaneous detection light collector 15 ... Optical fiber

Claims (3)

A scanning near-field microscope using an optical probe that irradiates light to an object from a probe,
  A light condensing system provided with a plurality of separate optical waveguides that regulate the waveguide direction of reflected light from the object;
  A light detection system provided with a photodetector on each side of the optical waveguide opposite to the side facing the object; and
  A scanning near-field microscope, wherein the light condensing system and the light detection system are arranged so as not to hinder displacement detection of the optical probe. The scanning near-field microscope according to claim 1, wherein a plurality or all of the optical signals detected by the respective photodetectors are integrated. Wherein the plurality or scanning near-field microscope according to claim 1 or 2 for separating the information from the signal storing and processing all of the optical signal the photodetector detects.

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