WO2022215638A1

WO2022215638A1 - Microscope and observation method

Info

Publication number: WO2022215638A1
Application number: PCT/JP2022/016356
Authority: WO
Inventors: 秀実重川
Original assignee: Ｇセラノスティックス株式会社
Priority date: 2021-04-07
Filing date: 2022-03-30
Publication date: 2022-10-13

Abstract

This microscope comprises: a probe; a first light output unit that outputs pulsed first light to the distal end of the probe; a sample platform that retains a sample being observed and a solution in which the sample is immersed; and a measurement unit that measures the tunnel current flowing between the probe and the sample, the tunnel current being caused by an electrical field produced by the first light.

Description

microscope, observation method

The present invention relates to microscopes and observation methods.

Scanning probe microscopes have high resolution and are used in various fields. However, the measurement in the liquid has a problem. Patent Document 1 discloses a method for measuring a sample surface placed in a liquid using a scanning probe microscope having a scanning tunneling microscope function and an atomic force microscope function; A cantilever having a conductive probe that probes a surface and an electrode electrically connected to the probe, the cantilever being covered with an insulator except for the tip of the probe and the electrode. wherein the cantilever is excited at the resonance frequency, and either the current flowing between the probe and the sample or the amplitude is controlled to a predetermined state while the other is monitored. A measurement method using a scanning probe microscope is disclosed.

Japanese Patent Laid-Open No. 10-132829

In the invention described in Patent Document 1, there is room for improvement in STM measurement in liquid.

A microscope according to a first aspect of the present invention comprises a probe, a first light output unit that outputs a first pulsed light to the tip of the probe, a sample to be observed, and a solution in which the sample is immersed. and a measurement unit for measuring a tunnel current flowing between the probe and the sample due to the electric field generated by the first light.
An observation method according to a second aspect of the present invention is an observation method for observing the sample immersed in the solution using a probe and a first light output unit that outputs a first pulsed light, disposing the tip of the probe near the sample; outputting the first light to the tip of the probe;
measuring a tunneling current flowing between the probe and the sample due to the electric field generated by the first light.

　According to the present invention, it is possible to perform STM measurement with little noise in a liquid.

Outline configuration diagram of the microscope Enlarged view showing the vicinity of the tip of the probe Functional configuration diagram of pump light output section, probe light output section, and measurement section A diagram showing the configuration of the first modulation section Schematic diagram of pump and probe beams Schematic configuration diagram of a comparative microscope as a comparative example Enlarged view showing the vicinity of the tip of the conventional probe Schematic diagram of a microscope in modified example 10 FIG. 12 is a diagram showing an example of a technique for fixing diamond particles to a pipette in modification 10; Enlarged view showing the vicinity of the tip of the probe in modified example 11

-First Embodiment-
A first embodiment of a microscope according to the present invention will be described below with reference to FIGS. 1 to 7. FIG.

(Constitution)
FIG. 1 is a schematic configuration diagram of a microscope T. As shown in FIG. The microscope T contains a pump light output section 2 that outputs a pump light 21, a probe light output section 3 that outputs a probe light 31, a probe 30, a measurement section 6, and a sample 90 observed by the microscope T. A sample table 91 is provided. In the following, the pump light 21 is also referred to as "second light", the pump light output section 2 is also referred to as "second light output section", the probe light 31 is also referred to as "first light", and the probe light output section 3 is referred to as "first light". It is also called a "first optical output section". As will be described later, a terahertz electric field is used for the probe light 31 in this embodiment.

The sample table 91 has a solution reservoir 92 which is a depression. Solution reservoir 92 is filled with solution 80 . A sample 90 to be observed is arranged in a solution reservoir 92 on a sample stage 91 . That is, sample 90 is immersed in solution 80 . Solution 80 is, for example, physiological saline, and sample 90 is, for example, microorganisms, cells, compounds, metals, and the like.

The tip of the probe 30 is arranged close to the sample 90 and the tip of the probe 30 is immersed in the solution 80 . The probe 30 is made of, for example, tungsten, nickel, or platinum iridium, and is processed so that the tip becomes thinner. No special treatment is applied to the side surface of the probe 30 . That is, the probe 30 is not provided with an insulating coating or the like.

FIG. 2 is an enlarged view showing the vicinity of the tip of the probe 30. As shown in FIG. In FIG. 2, the reference numeral 80 indicates an empty space for convenience of drawing, but it is intended to indicate that the probe 30 and the sample 90 are present in the solution 80. FIG. The tip of the probe 30 and the sample 90 are arranged very close, for example, at a distance of several nanometers, and the spot diameters of the pump light 21 and the probe light 31, which are large compared to this distance, are very large. Therefore, not only the tip of the probe 30 but also the solution 80 existing around the probe 30 is irradiated with the pump light 21 and the probe light 31 . The total current I _ALL is the sum of the tunnel current _I _T flowing between the sample 90 and the probe 30 and the ion current II generated by the electric field generated by the pump light 21 and the probe light 31 acting on the solution 80. . However, in this embodiment, the ion current _II can be ignored because the ions do not move for the reason described later. Therefore, since the total current I _ALL is the tunnel current I _T , the tunnel current I _T can be accurately measured. Returning to FIG. 1, the description continues.

The pump light output unit 2 irradiates the tip of the probe 30 with pulsed pump light 21 . The probe light output unit 3 irradiates the tip of the probe 30 with pulsed probe light 31 . An instantaneous electric field (voltage) is generated by irradiation of each of the pump light 21 and the probe light 31 . In this embodiment, CEP (Carrier Envelope Phase)-controlled pump light 21 is emitted to generate a desired electric field, the sample 90 is controlled, and the probe light 31 can be used to measure the change. Detailed configurations of the pump light output section 2 and the probe light output section 3 will be described later.

The pump light output unit 2 outputs a THz pulse having a period of 1 picosecond and a width of about 1 picosecond, which is obtained by irradiating a LiNiO ₃ crystal with an IR pulse light having a wavelength of 1034 nm and a width of 300 femtoseconds. The spot diameter of the pump light 21 in this embodiment is about 1 millimeter. The pump light 21 has its CEP controlled and is output with a constant phase.

The measurement unit 6 detects and records the electrons entering and exiting the sample 90, which serves as the counter electrode of the probe 30 in this embodiment, as the total current I _ALL . Whether the electrons flow from the probe 30 toward the sample 90 or from the sample 90 toward the probe 30 depends on the direction of the instantaneous electric field. The measurement unit 6 measures at least the tunnel current I _T that flows between the probe 30 and the sample 90 due to the electric field generated by the probe light 31 .

3 is a functional configuration diagram of the pump light output section 2, the probe light output section 3, and the measurement section 6. FIG. The pump light output section 2 includes a first light source 22 and a first modulation section 23 . The probe light output section 3 includes a second light source 32 , a second modulation section 33 and a delay adjustment section 34 . The measurement unit 6 includes a current preamplifier 61 , a lock-in amplifier 62 and a storage device 63 .

The first light source 22 of the pump light output unit 2 outputs pulsed laser light of about one cycle or less than one cycle at predetermined time intervals. The first light source 22 is, for example, a combination of a light source that outputs a pulsed laser with a pulse width of about 1 femtosecond and a LiNbO ₃ crystal. The first modulation section 23 adjusts the phase of the laser light output by the first light source 22 for the purpose of controlling the direction of the electric field. The configuration of the first modulating section 23 will be described later. The pump light output unit 2 outputs laser light output by the first light source 22 and modulated by the first modulation unit 23 .

The configuration of the second light source 32 of the probe light output section 3 is the same as that of the first light source 22 . The second modulation section 33 adjusts the phase of the laser light output from the second light source 32 and performs modulation for lock-in detection by the lock-in amplifier 62, for example, on-off modulation. For example, the second modulating section 33 has an optical chopper in addition to the configuration of the first modulating section 23 . The second modulation section 33 outputs the reference signal to the lock-in amplifier 62 at the timing when the light passes through the optical chopper. The delay adjustment unit 34 is a device that adjusts the output timing of the laser light output from the probe light output unit 3. For example, the optical path OP of the laser light including the mirror, the piezo element that drives the mirror, and the piezo element. Realized by combination with a controller. By using the delay adjustment unit 34, the time difference between the timing at which the sample 90 is irradiated with the pump light 21 and the timing at which the probe light 31 is irradiated to the sample 90 can be freely adjusted.

A current preamplifier 61 of the measurement unit 6 detects electrons entering and exiting the sample 90 as a total current I _ALL and outputs it to the lock-in amplifier 62 . The lock-in amplifier 62 operates based on the reference signal output from the second modulation section 33 , detects the modulation frequency component of the total current I _ALL , and outputs it to the storage device 63 . A storage device 63 is a non-volatile storage device such as a flash memory, and records the signal output by the lock-in amplifier 62 .

FIG. 4 is a diagram showing the configuration of the first modulating section 23. As shown in FIG. Reference characters OP indicated by hatching in FIG. 4 indicate optical paths of the pump light 21 . As shown in FIG. 4, a first lens 121 and a second lens 122 are arranged facing each other in the optical path OP. By passing the pump light 21 through the first lens 121 and the second lens 122, the pump light 21 can be controlled to a desired CEP.

The materials of the first lens 121 and the second lens 122 may both have transparency to the pump light 21, and the higher the transparency, the better. The shapes of the first lens 121 and the second lens 122 are preferably the same, and a spherical lens or a cylindrical lens can be selected according to the desired CEP aspect. When spherical lenses are arranged as the first and second lenses in the modulation section 3B, the pump light 21 of the cosine type (φcep=0) can be converted into that of the inverted cosine type (φcep=π). On the other hand, when cylindrical lenses are arranged as the first and second lenses, the cosine type pump light 21 can be converted into sin type (φcep=π/2). By controlling the phase of the pump light 21, the direction of the electric field can be controlled.

The phase of the pump light 21 can be switched by whether or not the pump light 21 is transmitted through the first lens 121 and the second lens 122 . For example, whether the cosine-type (φcep=0) pump light 21 is output as it is, whether it is output as an inverted cosin-type (φcep=π) by passing through a set of lenses, or whether it is output as φcep=π/2. switch.

The first lens 121 and the second lens 122 each have at least one entrance surface and one exit surface. The exit surface 121b of the first lens 121 and the entrance surface 122a of the second lens 122 are arranged to face each other. In FIG. 4, which is a specific example of the arrangement of spherical lenses, the first lens 121 and the second lens 122 are arranged such that the exit surface 121b of the first lens 121 and the entrance surface 122a of the second lens 122 are arranged. They are arranged so that THz waves are transmitted from the entrance surface 121a of the first lens 121 to the exit surface 121b and then transmitted from the entrance surface 122a of the second lens 122 to the exit surface 122b. When using a cylindrical lens, it is preferable to arrange them in the same way.

In addition to the configuration of the first modulation section 23 shown in FIG. 4, the second modulation section 33 has a configuration for performing modulation for lock-in detection, for example, a configuration in which an optical chopper is added.

FIG. 5 is a schematic diagram of pump light 21 and probe light 31. FIG. The upper part of FIG. 5 shows the timing of the pump light 21 and the probe light 31 that irradiate the probe 30, and the probe light 31 is irradiated after the pump light 21 is irradiated. After a while, the pump light 21 is applied again. The time from the irradiation of the pump light 21 to the irradiation of the probe light 31 is the aforementioned delay time.

The lower part of FIG. 5 shows main waveforms of the pump light 21 and the probe light 31. The horizontal axis represents time, and the vertical axis represents the distance between the probe 30 and the sample 90 due to the irradiated pump light 21 and probe light 31. shows the electric field applied to In the example shown in FIG. 5, it is zero until time t1, becomes negative from time t1 to time t2, reaches a positive peak at time t3, and decreases to zero at time t4. It is negative from time t4 to time t5, and is zero thereafter. Note that times t1 to t5 are, for example, about 1 picosecond. Also, the lower part of FIG. 5 merely shows the main waveforms, and does not completely become zero before time t1 or after time t5.

At this time, if the integral value of the electric field from time t1 to t2 is area A1, the integral value of the electric field from time t2 to t4 is area A2, and the integral value of the electric field from time t4 to t5 is area A3, the sum of A1 and A3 is It has a relationship approximately equal to A2. Therefore, since the integral value of the electric field from time t1 to t5 is almost zero, ions in the region of the solution 80 irradiated with the pump light 21 and the probe light 31 start moving at time t1, but return to normal at time t5. position. In addition, the time period during which the electric field is applied is very short, and the generated electric field is strong only directly under the probe 30 due to the effect of probe enhancement, so that the effect is limited to a narrow range in both the time domain and the space domain. do not have. That is, the ion current _II can be ignored regardless of whether the pump light 21 or the probe light 31 is applied.

(Comparative example)
FIG. 6 is a schematic configuration diagram of a comparative microscope, which is a comparative example, and corresponds to FIG. 1 of the present invention. The structure of the sample stage 91 is the same as in FIG. 1, and the sample 90 immersed in the solution 80 is arranged in the solution reservoir 92 . The tip of the conventional probe Z is placed close to the sample 90 and the tip of the conventional probe Z is immersed in the solution 80 . A predetermined constant voltage is applied to the conventional probe Z from the applying section 7 . Conventionally, the side surface of the probe Z is insulated. The measurement unit 6 detects the electrons flowing into the sample 90, which conventionally serves as the counter electrode of the probe Z, as the total current I _ALL using the current preamplifier 61 .

FIG. 7 is an enlarged view showing the vicinity of the tip of the conventional probe Z. FIG. Note that the range shown in FIG. 7 is all in the solution 80 . A voltage is applied to the conventional probe Z, but the side surface of the conventional probe Z is coated with an insulating coating agent, and only the tip of the conventional probe Z is exposed from the insulating coating. When the conventional probe Z comes close enough to the sample 90, a tunnel current _{IT flows between the conventional probe Z and the sample 90, so the measuring unit 6 measures the total current IALL} _including this tunnel current _IT . .

As described above, the voltage is constantly applied to the conventional probe Z from the application unit 7. Therefore, even if the conventional probe Z and the sample 90 are separated from each other to some extent, the sample 90 is exposed to the liquid 80 via the solution 80. An ion current _II flows. The total current I _ALL measured by the measurement unit 6 is the sum of the tunnel current _I _T and the ion current II. The tunnel current _IT is very small compared to the ion current _II , and even if the tunnel current _IT is generated, it is very difficult to detect it if it is smaller than the fluctuation width of the ion current _II .

On the other hand, in the present invention, there is no voltage constantly _applied to the probe 30, and the pump light 21 and the probe light 31 are irradiated only for a very short period of time. can be ignored. Therefore, in the present invention, there is no difficulty in measuring the tunnel current _IT as in the prior art, and STM (Scanning Tunneling Microscope) measurement with little noise even in liquid can be realized.

According to the first embodiment described above, the following effects are obtained.
(1) The microscope T includes a probe 30, a probe light output unit 3 that outputs a probe light 31 that is a pulsed first light to the tip of the probe 30, a sample 90 to be observed, and a sample 90 that is immersed. and a measuring unit 6 for measuring a tunneling current I _T flowing between the probe 30 and the sample 90 due to the electric field generated by the probe light 31 . In the prior art shown in FIGS. 6 and 7, a voltage is constantly applied to the probe 30, but the microscope T measures the tunneling current I _T caused by the pulsed probe light 31. can perform STM measurements with little noise.

(2) A terahertz electric field is used for the probe light 31, which is the first light, and the time width is 1 picosecond or less. Therefore, the movement of ions contained in the solution 80 is small, and the adverse effect of the ion current _II _on the measurement of the tunnel current IT can be suppressed.

(3) The first light has a substantially zero integral value of the electric field generated by one pulse. Therefore, the movement of ions contained in the solution 80 is suppressed, and the ion current _II can be ignored.

(4) The microscope T includes a pump light output unit 2 that outputs a pump light 21, which is a pulsed second light, to the tip of the probe 30; and a delay adjustment unit 34 that adjusts the delay time, which is the difference from the timing at which the signal is received. The delay adjuster 34 changes the delay time in a plurality of ways. Therefore, it is possible to measure the dynamics of a sample 90 immersed in the solution 80, such as a cell.

(Modification 1)
In the embodiment described above, both the pump light 21 and the probe light 31 are applied to the probe 30 . However, only the probe light 31 may be irradiated without irradiating the pump light 21 . In this case, the dynamics of the sample 90 cannot be measured, but the characteristics of the sample 90 in liquid can be measured with a simpler configuration than the above-described embodiment.

(Modification 2)
In the above-described embodiment, the probe 30 may be made of a material that does not reflect light, such as gold or silver. In this case, since the light is easily reflected, the probe 30 is less likely to absorb heat, and the influence of heat such as thermal expansion of the probe can be reduced.

(Modification 3)
In the embodiment described above, both the pump light 21 and the probe light 31 generated substantially zero integral values of electric fields. However, at least one of the pump light 21 and the probe light 31 does not have to have an integral value of the generated electric field that is substantially zero. In this case, it is conceivable that the ions in the solution 80 move little by little and the ion current _II cannot be ignored. This effect can be reduced by shortening the time of . For example, the times t1 to t5 may be set to 100 femtoseconds, which is 1 picosecond or less.

(Modification 4)
In the embodiments described above, both the pump light 21 and the probe light 31 were CEP controlled. However, controlling the CEP of the pump light 21 is not an essential configuration. For example, the pump light 21 may be a normal ultrashort pulse whose phase is not controlled. Moreover, when the CEP of the pump light 21 is not controlled, the pump light 21 to be emitted is not limited to one cycle or less, and may include a plurality of cycles.

(Modification 5)
In the above-described embodiment, the pulse time of the pump light 21 and the probe light 31, that is, the time from t1 to t5 in FIG. 5, is about 1 picosecond. However, the pulse time is not limited to this, and may be shorter than 1 picosecond or longer than 1 picosecond. For example, the pulse duration may be in macroseconds, nanoseconds or femtoseconds, depending on the phenomenon being measured.

(Modification 6)
In the embodiments described above, the pump light output section 2 was equipped with a first light source 22, the probe light output section 3 with a second light source 32, and the microscope T with a total of two light sources. However, the microscope T may be configured with only one light source. In this case, the laser light output from the common light source is split into two by a beam splitter, and the two are input to the first modulating section 23 and the second modulating section 33, respectively. Note that one laser beam may be input to the delay adjustment unit 34 before being input to the second modulation unit 33 and the output of the delay adjustment unit 34 may be input to the second modulation unit 33 .

(Modification 7)
Although the sample stage 91 has the solution reservoir 92 in the above-described embodiment, it is not essential for the sample stage 91 to have the solution reservoir 92 . Instead of the sample table 91 having the solution reservoir 92 , a container containing the solution 80 and the sample 90 may be placed on the sample table 91 .

(Modification 8)
In the embodiment described above, the ion current _II was neglected. However, the waveform of the electric field applied between the probe 30 and the sample 90 is accurately obtained, the effect of the electric field on the ions in the solution 80, that is, the magnitude of the ion current II is calculated, and the tunnel current _I _T may be calculated. Accurately obtaining the waveform of the electric field enables detailed evaluation of physical information and precise time-resolved measurement.

(Modification 9)
The configuration of the first modulating section 23 may be as follows. That is, the first modulating section 23 may be a combination of a half-wave plate and a wire grid polarizer. In this case, the light output from the first light source 22 is input to the half-wave plate, and the output is input to the wire grid polarizer. In this configuration, the phase of the pump light 21 can be freely set by rotating the half-wave plate.

(Modification 10)
The probe 30 described above may be configured as a part of the ion conductance microscope, specifically as a metal coating covering the tip of the pipette 811 with which the probe 30 constitutes the ion conductance microscope. FIG. 8 is a schematic diagram of the microscope T2 in the tenth modification. However, in FIG. 9, the pump light output section 2, the probe light output section 3, and the measurement section 6, which are common to FIG. 1, are omitted. Microscope T2 also functions as an ion conductance microscope. The microscope T2 further includes a pipette 811, a first electrode 812, a second electrode 814, and ancillary devices (not shown) in addition to the pump light output section 2, the probe light output section 3, and the measurement section 6 described above. Prepare. Microscope T2 has two modes of operation: ion conduction mode and tunneling mode.

A pipette 811 is a hollow pipette made of glass and arranged on an XYZ stage (not shown). The inside of the pipette 811 is filled with the solution 80 and the first electrode 812 is inserted inside the pipette 811 . A constant voltage is applied to the second electrode 814 in the ion conduction mode, and current flows between the first electrode 812 and the second electrode 814 through the solution 80 . Since the magnitude of this current depends on the distance between the pipette 811 and the sample 90, the surface shape of the sample 90 can be measured with high accuracy. In the ion conduction mode, the pump light output section 2, the probe light output section 3, and the measurement section 6 do not operate.

In the tunnel mode, a constant voltage is not applied to the second electrode 814, and the tip of the pipette 811 is irradiated with the pump light 21 and the probe light 31. That is, in this modified example, the pipette 811 functions as the probe 30 in the embodiment. An enlarged view of the tip of pipette 811 is shown at the bottom of FIG.

The lower part of FIG. 8 is a conceptual diagram showing the tip of the pipette 811. The tip of pipette 811 has a diameter of several nanometers to several hundreds of nanometers, for example, 100 nm, and diamond particles 8112 are fixed by cross-linking agent 8111 . Various cross-linking agents 8111 can be used. For example, diamond particles 8112 can be fixed to pipette 811 by the method shown in FIG. The diamond particles contain diamond nitrogen-vacancy centers, which are a type of lattice defect. Diamond nitrogen-vacancy centers are also called nitrogen-vacancy centers or NV centers. In this modification, diamond nitrogen-vacancy centers are referred to as "diamond NV".

The tip of the pipette 811 is coated with a metal coating 8112A. The metal coating 8112A may be applied not only to the tip of the pipette 811, but also to the side of the pipette 811 and the area near the tip. The metal coating 8112A may not be applied to some areas of the tip of the pipette 811 . This metal coating 8112A is, for example, gold, silver, and platinum. This metal coating 8112A can be applied to pipette 811 by any method.

FIG. 9 is a diagram showing an example of a technique for fixing the diamond particles 8112 to the pipette 811. FIG. As shown in FIG. 9, there is a metal coating 8112A, eg gold, between the diamond particle 8112 and the pipette 811. In this case, the diamond is bound with a carbodiimide crosslinker 8113 and the pipette 811 tip is bound with an amino-terminated alkanethiol 8115 . Diamond particles 8112 are fixed to pipette 811 by binding carbodiimide cross-linking agent 8113 and amino-terminated alkanethiol 8115 .

In this modified example, the tunnel current flowing between the tip of the pipette 811 and the sample 90 due to the electric field generated by the probe light 31 is measured. In this modified example, measurement unit 6 is connected to sample 90 and metal coating 8112A to measure the tunnel current flowing between the tip of pipette 811 and sample 90 . According to this configuration, it is possible to measure the tunneling current in the liquid using part of the configuration of the ion conductance microscope.

It should be noted that a function as a Raman spectroscopic microscope may be further added in Modified Example 10. In this case, the pump light 21 or the probe light 31 may be used as excitation light for causing Raman scattering or Rayleigh scattering. Scattered light is detected by a detector (not shown). In addition, by using the pipette 811 described above, the scattered light is enhanced by the effect of enhancing the probe, making detection easier and enabling observation in a short period of time. Diamond NV also makes it possible to obtain information such as local temperature and local electromagnetic field.

(Modification 11)
FIG. 10 is an enlarged view showing the vicinity of the tip portion of the probe 30 in the eleventh modification. That is, in the above-described embodiment, a diamond probe including an NV center coated with a metal coating C may be used as the probe 30 . In this case, excitation light for exciting NV centers, such as probe light 31, is applied from above to a position of the diamond probe not covered with the metal coating C, for example. Fluorescence from the NV center is also extracted from above. However, the excitation light for exciting this NV center does not have to be CEP-controlled. By using this probe 30, the spatial resolution of the STM can be improved.

Furthermore, this probe may be used to construct a Raman spectroscopic microscope. When constructing a Raman spectroscopic microscope, for example, the pump light 21 is used as excitation light for causing Raman scattering or Rayleigh scattering, and the range indicated by the dashed line in FIG. 10 is irradiated. As a result, Raman spectroscopy with a spatial resolution higher than that of Modification 10 is obtained. In FIG. 10, the entire periphery of the tip of the probe 30 is covered with the metal coating C, but only a predetermined angular range of the probe 30 may be covered with the metal coating C.

(Modification 12)
In the embodiment described above, the sample 90 was immersed in the liquid solution 80 . However, in the above-described embodiment, only the state in which the sample 90 is immersed in the solution 80 is shown as an environment in which the STM measurement is not easy. you can go

Each of the above-described embodiments and modifications may be combined. Although various embodiments and modifications have been described above, the present invention is not limited to these contents. Other aspects conceivable within the scope of the technical idea of the present invention are also included in the scope of the present invention.

T, T2...Microscope 2...Pump light output section 3...Probe light output section 3B...Modulation section 6...Measurement section 21...Pump light 22...First light source 23...First modulation section 30...Probe 31...Probe light 32... Second light source 33 Second modulation section 34 Delay adjustment section 80 Solution 90 Sample 91 Sample stage

Claims

a probe;
a first light output unit that outputs a pulsed first light to the tip of the probe;
a sample table holding a sample to be observed and a solution in which the sample is immersed;
and a measurement unit that measures a tunneling current flowing between the probe and the sample due to the electric field generated by the first light.
A microscope according to claim 1, wherein
The microscope, wherein the first light has a duration of 10 nanoseconds or less.
In the microscope according to claim 1 or claim 2,
The microscope, wherein the first light has a substantially zero integral value of an electric field generated by one pulse.
In the microscope according to any one of claims 1 to 3,
a second light output unit that outputs a pulsed second light that excites the sample to the tip of the probe;
a delay adjustment unit that adjusts a delay time that is the difference between the timing at which the first light is emitted and the timing at which the second light is emitted;
The microscope, wherein the delay adjuster changes the delay time in a plurality of ways.
A microscope according to claim 4,
The microscope, wherein each of the first light and the second light has a time width of 10 nanoseconds or less.
A microscope according to claim 1, wherein
The microscope, wherein the probe is a metal coating covering the tip of a pipette constituting an ion conductance microscope.
A microscope according to claim 1, wherein
The microscope, wherein the probe is a metal-coated diamond containing NV centers.
An observation method for observing a sample immersed in a solution using a probe and a first light output unit that outputs a first pulsed light,
disposing the tip of the probe near the sample;
outputting the first light to the tip of the probe;
and measuring a tunneling current flowing between the probe and the sample due to the electric field generated by the first light.