WO2005119206A1

WO2005119206A1 - Method and device for controlling photo-excitation q value of vibrator

Info

Publication number: WO2005119206A1
Application number: PCT/JP2005/010128
Authority: WO
Inventors: Hideki Kawakatsu
Original assignee: Japan Science And Technology Agency
Priority date: 2004-06-02
Filing date: 2005-06-02
Publication date: 2005-12-15
Also published as: JPWO2005119206A1

Abstract

There are provided a method and a device for controlling the photo-excitation Q value capable of improving sensitivity by feeding back the speed measured by a speed meter to an excitation signal by the vibrator photo-excitation Q value control, thereby canceling the attenuation term. The photo-excitation Q value control device includes a vibrator (4) arranged in a liquid, the excitation light (10) and measurement light (11) applied to the vibrator (4) and a light input/output unit (9) for inputting/outputting the excitation light (10) and the measurement light (11) of the vibrator (4), a supply unit for supplying the excitation light and the measurement light to the light input/output unit (9), and a position/speed detection unit for apparently increasing the Q value of the vibrator according to the return light of the measurement light from the light input/output unit (9) and detecting the position and speed of the vibrator.

Description

Specification

Optical excitation of oscillator Q value control method and device

Technical field

The present invention relates to a method and an apparatus for controlling the Q value of light excitation of a vibrator, and more particularly to a method and apparatus for controlling the Q value of light excitation of a vibrator in a liquid. Background art

[0002] Conventionally, by using a piezo element as an excitation device and feeding back a velocity term and a position term obtained by phase-shifting or differentiating the position term of an oscillator with an appropriate phase difference, an apparent Q of the oscillator is obtained. There was a technique to improve the value.

[0003] Also, there is disclosed an excitation device in which a magnetic field coil is provided outside a liquid, and a magnetic substance is applied to a cantilever such as silicon in the liquid to perform excitation (see Non-Patent Document 1 below). There is also a technique for vibrating a vibrator in a liquid with light.

[0004] Furthermore, the present inventor has proposed a laser Doppler interferometer having an optical excitation function for a sample and an excitation method of a cantilever (see Patent Document 1 below).

Patent Document 1: JP 2003-114182 A

Non-Patent Literature 1: Enhanced imaging oi DNA via active quality factor control, "A. DL L. Humphris, A. N. Round, M. J. Miles, Surface Science, 491, 468-472, 2001.

Disclosure of the invention

[0005] The cantilever (vibrator) is a problem in the measurement using the dynamic characteristics of the cantilever, in which the Q value is greatly attenuated due to viscosity in a liquid compared to vacuum and air. In addition, since the conventional Q value control does not directly measure the speed, there is no true speed term feedback, and there is a problem that the Q value cannot be increased to some extent.

[0006] In view of the above situation, the present invention cancels the attenuation term by directly measuring the speed and feeding back the attenuation of the Q value to the excitation signal by controlling the optical excitation Q value of the vibrator. Another object of the present invention is to provide a method and an apparatus for controlling the Q value of optical excitation of a vibrator capable of improving sensitivity. [0007] In order to achieve the above object, the present invention provides:

[1] A method of controlling the Q value of the oscillator by optical excitation, in which the Q value of the oscillator is controlled by feeding back the speed of the oscillator in the liquid directly measured by velocity measurement to the optical excitation device during optical excitation. It is characterized by apparently increasing the sensitivity as a vibrator.

[2] According to the method of controlling the optical excitation Q value of the vibrator according to the above [1], the vibrator is irradiated with excitation light and measurement light, and return light of the measurement light of the vibrator is detected. And measuring the speed of the vibrator in the liquid.

[3] Optical excitation of oscillator In the Q value control method, in optical excitation, the speed directly measured by measuring the position and velocity of the oscillator in a liquid is fed back to the optical excitation device, The value is apparently increased, and the sensitivity as this oscillator is enhanced.

[4] According to the method of controlling the optical excitation Q value of the vibrator according to the above [1], the vibrator is irradiated with excitation light and measurement light, and return light of the measurement light of the vibrator is detected. In addition, the velocity and the velocity directly measured by measuring the position and velocity of the vibrator in the liquid are characterized.

[5] The method for controlling the Q value of light excitation of a vibrator according to the above [1] or [3], wherein the liquid is water.

[6] The method of controlling the Q value of light excitation of a vibrator according to the above [1] or [3], wherein the liquid is ethanol.

[7] The method of controlling the Q value of light excitation of a vibrator according to the above [1] or [3], wherein the Q value control is applied to a large number of vibrators immersed in a liquid by optical scanning. And

[8] The method for controlling the Q value of light excitation of a vibrator according to the above [7], wherein a number of points in a cell immersed in a liquid are measured.

[9] Optical Excitation In the Q-value control device, a vibrator arranged in a liquid, a light-emitting / incident section for emitting and emitting excitation light and measurement light applied to the vibrator, A speed at which the Q value of the vibrator is apparently increased based on a supply portion of the excitation light and the measurement light to the incident portion and a return light of the measurement light from the light output / incident portion, and the speed of the vibrator is directly detected. And a degree detector. [10] In the optical excitation Q-value control device according to the above [9], the speed detector is a heterodyne laser Doppler interferometer, and a bandpass filter and a phase shift circuit are provided on the output side of the speed detector. An amplifier is connected in series, and a feed knock is applied to the pump light supply section.

[11] Optical Excitation In the Q-value control device, a vibrator arranged in a liquid, a light-emitting / incident part for emitting and emitting excitation light and measurement light applied to the vibrator, The Q value of the vibrator is apparently increased based on the supply section of the excitation light and the measurement light to the incidence section and the return light of the measurement light from the light exit / incidence section, and the position and speed of the vibrator are detected. It is characterized by comprising a position / velocity detecting unit.

[12] In the optical excitation Q value control device according to the above [11], the position / velocity detecting unit is a heterodyne laser Doppler interferometer, and a band-pass filter is provided on the output side of the position / velocity detecting unit. And a phase shift circuit and an amplifier are connected in series, and the feedback is provided to the pumping light supply unit.

[13] In the optical excitation Q value control device according to the above [11], the speed detection unit

And a heterodyne laser Doppler interferometer, a superheterodyne circuit is connected to the heterodyne laser Doppler interferometer, and a feed knock is supplied to the excitation light supply unit.

[14] In the optical excitation Q-factor control device according to the above [11], the position / velocity detecting section comprises a heterodyne laser Doppler interferometer, and a superheterodyne circuit is connected to the heterodyne laser Doppler interferometer. Then, feedback is provided to the excitation light supply section.

[15] The optical excitation Q-value control device according to the above [9] is characterized in that a phase shift circuit whose frequency characteristic is flat near the resonance frequency by feedback is used.

[16] The optical excitation Q value control device according to the above [9], wherein the phase shift circuit is of a feedback type using CdS and LED cells.

[17] The optical excitation Q value control device according to the above [9], characterized in that the device controls the vibration characteristics of the cantilever of the scanning force microscope.

Brief Description of Drawings FIG. 1 is an overall configuration diagram of an embodiment of the present invention.

FIG. 2 is a schematic view of a cantilever (vibrator) showing an embodiment of the present invention.

FIG. 3 is a vibration characteristic diagram (part 1) of a cantilever using a Q value control according to the present invention.

FIG. 4 is a vibration characteristic diagram of a cantilever using the Q value control of the present invention in which the vertical axis in FIG.

5 is a vibration characteristic diagram (2) of the cantilever using the Q value control of the present invention shown in FIG. 3.

FIG. 6 is a diagram showing a comparison of vibration characteristics of a cantilever in ethanol and water.

FIG. 7 is a diagram showing vibration characteristics of a cantilever when a force is applied without performing Q value control according to the present invention.

FIG. 8 is a diagram of a phase shift circuit having a flat frequency characteristic in the vicinity of the resonance frequency due to the feedback of the present invention.

FIG. 9 is a frequency characteristic diagram of a phase shift circuit having a flat frequency characteristic near the resonance frequency shown in FIG.

10 is a vibration characteristic diagram (part 1) of the cantilever in the case where the phase shift circuit shown in FIG. 8 is used as the phase shift circuit in the apparatus of the present invention shown in FIG.

FIG. 11 is a vibration characteristic diagram (part 2) of the cantilever when the phase shift circuit shown in FIG. 8 is used as the phase shift circuit in the apparatus of the present invention shown in FIG. 1.

FIG. 12 is a diagram showing a change in vibration characteristics when a self-generated molecular film is generated on the cantilever in the control of the vibration characteristics of the cantilever using the Q value control applied to the present invention.

FIG. 13 is a partial configuration diagram of a system showing another embodiment of the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

[0025] In the optical excitation Q-value control device, a vibrator placed in a liquid, a light output / incident part for transmitting and receiving excitation light and measurement light applied to the vibrator, The Q value of the vibrator is apparently increased based on the supply section of the excitation light and the measurement light to the incident section and the return light of the measurement light from the light output / incident section, and the position and speed of the vibrator are detected. Position 'speed A degree detection unit. In addition, a phase shift circuit having a flat frequency characteristic near the resonance frequency by feedback is provided. Therefore, the Q value of the vibrator can be controlled, which can contribute to the improvement of the sensitivity of the vibrator sensor.

[0026] Furthermore, since the velocity can be directly measured by the heterodyne laser Doppler meter, it is possible to measure the position and obtain the derivative thereof electrically, thereby obtaining a device that is more resistant to noise than a device that obtains the speed signal. it can. In addition, since the speed is obtained by the heterodyne laser Doppler meter, the frequency of the heterodyne measurement and the vibration frequency are set to be greatly different, and interference between measurement and excitation is extremely small. High and high Q values can be realized by controlling the Q value.

Example

Hereinafter, embodiments of the present invention will be described in detail.

FIG. 1 is an overall system configuration diagram showing an embodiment of the present invention, and FIG. 2 is a schematic diagram of a cantilever (vibrator) portion thereof.

[0029] In this figure, 1 is a liquid container, 2 is a sample in the liquid container 1, 3 is a cover glass, 4 is a cantilever (vibrator), 5 is an excitation laser device (LD), 6 is an excitation laser device 5 Excitation light (λ = 780 nm) An optical fin that propagates 10, 7 is the first PBS (Volarising beam splitter), 8 is the second PBS, 9 is the light input / output section (sensor head) [phase plate and Objective lens (not shown)], 11 is the measurement light (ぇ = 63211111), 12 is the optical fiber that propagates the measurement light 11, 13 is connected to the optical fiber 12, and irradiates the measurement light 11 A heterodyne laser Doppler interferometer that receives the return light of the measurement light 11 from the force cantilever 4 and measures the position and / or velocity of the cantilever 14 is a heterodyne laser Doppler interferometer. Van connected to 13 output side Pasufiru data (f

c

= lkHz, 1ΜΗζ), 15 is a phase shift circuit connected to the band-pass filter 14, 16 is an amplifier connected to the phase shift circuit 15, 17 is connected to the pump laser device 5 and An adder connected to the amplifier 16 is connected to the output side of the adder 17 and a servo analyzer connected to the output side of the heterodyne laser Doppler interferometer 13. Note that, as shown in Fig. 2, By irradiating the excitation light and the measurement light, highly accurate measurement can be performed. However, the excitation light and the measurement light may be bundled and applied to the same portion of the cantilever. When the excitation light and the measurement light are bundled in this way, there is an advantage that light scanning can be easily performed, particularly when a large number of cantilevers are arranged.

[0030] Therefore, the excitation light 10 emitted from the excitation laser device (LD) 5 is applied to the cantilever 4 via the optical fiber 6 → the first PBS 7 → the second PBS 8 → the light exit / incident section 9 and The measurement light 11 is also irradiated on the cantilever 4. Then, the cantilever 4 is optically excited, and the return light of the measurement light 11 returns to the light entrance / exit portion 9 → the second PBS 8 → the optical fiber 12 → the heterodyne laser Doppler interferometer 13 and the heterodyne laser Doppler interferometer 13 Then, the position and / or speed of the cantilever 4 is measured by a difference signal between the measurement light 11 and the return light of the measurement light. The output from the heterodyne laser Doppler interferometer 13 is input to the servo analyzer 18 and the heterodyne laser Doppler interferometer 13 → bandpass filter 14 → phase shift circuit 15 → amplifier 16 → adder 17 → pump laser 1 This is fed back to the device (LD) 5.

According to the present invention, in the method of controlling the Q value of light excitation of a vibrator, the Q value of the vibrator is apparently increased by feeding back the speed of the vibrator in a liquid to the light excitation device in the light excitation. It is characterized by increasing the sensitivity as a function.

[0032] The present invention also relates to an optically-excited Q-value control device, comprising: a vibrator disposed in a liquid; and a light output / incident section for transmitting and receiving excitation light and measurement light applied to the vibrator. The Q value of the vibrator is apparently increased based on the supply section of the excitation light and the measurement light to the light exit / incident section and the return light of the measurement light from the light exit / incident section, and the speed of the vibrator is increased. And a speed detecting unit for detecting the speed.

Further, the oscillator is irradiated with excitation light and measurement light, the return light of the measurement light from the oscillator is detected, and the speed of the oscillator in the liquid is measured. In particular, since the speed can be directly measured by a heterodyne laser Doppler interferometer, the position can be measured, and its derivative can be obtained electrically to obtain a device that is more resistant to noise than a device that obtains a speed signal. . Also, it can be applied to a highly integrated cantilever array and can be used for optical scanning. Further, the liquid vibration is small, that is, noise can be reduced. [0034] Also, in the optical excitation of the vibrator (small cantilever), by returning the position term and the velocity term respectively, the damping term due to the environment in which the vibrator is placed is canceled, and the Q value of the vibrator is returned. Can be changed in appearance.

In the experiment, a commercially available contact mode cantilever (length 1 = 100 μm, width = 20111, thickness t = 0.08 m) was used as a vibrator. The resonance frequency was 69 kHz, and the other conditions used were a 10x objective lens (olympus, no IR correction, for air / vacuum), and a heterodyne laser Doppler interferometer capable of measuring up to 100 MHz. The LD current as an excitation laser device is 51.8 mA.

FIG. 3 is a vibration characteristic diagram (No. 1) of the cantilever using the Q value control of the present invention. In FIG. 3, the horizontal axis represents frequency (kHz), and the vertical axis represents amplitude (nm). ing. Here, underwater optical excitation is performed, and the cantilever for the Olympus contact mode cantilever width 20 μm, length 100 μm, thickness 0.8 m, resonance frequency in vacuum is 78 kHz, feedback The speed signal gain is changed while measuring. The phase difference Δφ between the input and output of the phase shift circuit 15 is fixed at 90 degrees.

In this figure, curve a has Q value control (the present invention: gain 6), curve b has Q value control (the present invention: gain 4), and curve c has Q value control (the present invention: gain). 2), Curve d is without Q value control. As is clear from this figure, the Q value was improved by the Q value control of the present invention.

FIG. 4 is a vibration characteristic diagram of a cantilever using the Q value control of the present invention, in which the vertical axis of FIG. 3 is logarithmicly displayed, and a second-order mode appears.

FIG. 5 is a vibration characteristic diagram (part 2) of the cantilever using the Q value control of the present invention shown in FIG. In this figure, curve a has Q value control (invention: gain 7), curve b has Q value control (invention: gain 5), curve c has Q value control (invention: gain 4), Curve d has Q value control (invention: gain 3), and curve e has no Q value control.

[0040] As is apparent from this figure, in the present invention, the Q value can be improved by the Q value control. Also, it became clear that the Q value could be increased as the gain increased. FIG. 6 is a diagram showing a comparison of vibration characteristics of cantilevers in ethanol and water. In this figure, curve a shows the case of water and curve b shows the case of ethanol.

[0042] In this figure, the force that tried to measure in ethanol under the same conditions as in Figs.

It is thought that ethanol is self-excited because it is less viscous than water.

As is apparent from this figure, ethanol having a lower viscosity is shifted to a higher resonance frequency.

Further, as compared with FIG. 7 showing the result when the Q value control of the present invention is not performed, the difference in the shift amount of the resonance frequency due to the difference in the viscosity is smaller. This is due to the fact that the attenuation factor was apparently reduced by the Q factor control. In FIG. 7, a is water, b is ethanol, and c is a 1: 1 solution of water and ethanol.

FIG. 8 is a diagram of a phase shift circuit having flat frequency characteristics in the vicinity of the resonance frequency due to the feedback of the present invention. Note that this phase shift circuit corresponds to the phase shift circuit 15 in FIG.

[0046] In this figure, a 21-bit input signal, a 22-bit CdS—LED sensor, 23, 24, 26, 29, 30, 31 are amplifiers (op-amps), 25 and 27 are comparators, and 28 is a multiplier. (Multiplier), 32 is a transistor, 33 is an output signal, V is -10V, V is + 10V.

EE CC

Here, the input signal 21 input from the bandpass filter 14 (see FIG. 1) is

(See FIG. 1), but the phase shift relationship between the two is realized by the feedback by the CdS—LED cell 22 so that the phase shift is flat regardless of the frequency.

FIG. 9 shows the result of obtaining a flat phase shift characteristic by the phase shift circuit shown in FIG. In FIG. 9, A is a line showing the flat phase shift characteristic output by the phase shift circuit of the present invention, and B is a line showing the phase shift characteristic output by the conventional phase shift circuit (having no feedback function). is there.

[0049] As shown in this figure, according to the phase shift circuit of the present invention, it is important to be able to obtain a flat gain (dB) regardless of the frequency.

FIG. 10 is a vibration characteristic diagram (part 1) of the cantilever when the phase shift circuit shown in FIG. 8 is used as the phase shift circuit in the apparatus of the present invention shown in FIG. When the optical excitation Q control according to the present invention is not performed, the force with Q value of 2 is obtained in C. When the optical excitation Q control is performed according to the present invention, the Q value is 620 in D, and unintended oscillation occurs. Do not arise Is shown.

FIG. 11 is a vibration characteristic diagram (part 2) of the cantilever when the phase shift circuit shown in FIG. 8 is used as the phase shift circuit in the apparatus of the present invention shown in FIG. It can be seen that the phase changes sharply at the resonance frequency because the apparent Q value is increased. In other words, it indicates that the detection of fields and masses by the cantilever can be realized with high sensitivity.

FIG. 12 is a diagram showing a change in vibration characteristics when a self-generated molecular film is generated on the cantilever in the vibration characteristic control of the cantilever using the Q value control according to the present invention. In Fig. 12, E (corresponding to D in Fig. 10) is the characteristic when the cantilever vibrates in pure water using the Q-value control, and F and G are trace amounts of self-generated molecules using the Q-value control. This shows that the cantilever vibrates in a mixed state, indicating that the cantilever using the Q value control is sensitive to the adsorption of self-generated molecules. Estimates show that mass detection on the order of fg to pg is realized.

In the method of controlling the Q value of light excitation of a vibrator, the Q value control can be applied to a large number of vibrators immersed in a liquid by optical scanning.

[0054] Furthermore, in the method of controlling the Q value of light excitation of a vibrator, since Q value control can be applied to a large number of vibrators immersed in a liquid, it is possible to measure a large number of points in cells immersed in the liquid. it can. Furthermore, the Q-value control method of the vibrator optical excitation is adapted to the vibration control of one or many cantilevers immersed in liquid, and a high-resolution scanning force microscope can be realized.

FIG. 13 is a partial configuration diagram of a system showing another embodiment of the present invention. That is, a part of the system in Fig. 1 is modified.

As shown in FIG. 13, reference numeral 40 denotes a superheterodyne circuit. This superheterodyne circuit 40 includes a local oscillator 41, mixers (frequency mixers) 42 and 45, and a bandpass filter 4

3, consisting of 44 phase shift circuits (no feedback function).

Here, the local oscillator 41 has only the frequency f output from the servo analyzer 18.

1 0 low or frequency f Output a higher f. The output frequency of the heterodyne laser Doppler interferometer 13 is

2

Servo 'frequency output from analyzer 18 f

1

Is equal to In the present invention, since the frequency f itself changes, the condition of the local oscillator 41 described above is satisfied.

1

Frequency f + f

Ten

Or generate f -f.

Ten

As described above, in the optical excitation Q-factor control device of the present invention, the speed detecting section is constituted by the heterodyne laser Doppler interferometer 13, and the superheterodyne circuit 40 is connected to the heterodyne laser Doppler interferometer 13. Then, a feedback is provided to an excitation laser device (LD) 5 (see FIG. 1) which is a pump light supply unit.

[0059] In the optical excitation Q value control device of the present invention, the position / velocity detecting unit comprises a heterodyne laser Doppler interferometer 13, and a superheterodyne circuit 40 is connected to the heterodyne laser Doppler interferometer 13. Then, feedback is provided to the pump laser device (LD) 5 (see Fig. 1), which is the pump light supply unit. In such a configuration, a conventional phase shift circuit having no feedback function can be used as the phase shift circuit 44.

[0060] The present invention is not limited to the above-described embodiments, and various modifications are possible based on the spirit of the present invention, and these are not excluded from the scope of the present invention.

According to the present invention, the following effects can be obtained.

[0062] (1) In optical excitation, by combining with a photodetector that detects displacement or velocity, it is possible to use a transducer or transducer array as a sensor simply by irradiating light. In addition, Q-control can improve the sensitivity of substance detection and improve the image when used on a scanning probe microscope cantilever. In other words, it can be expected that Q-value control will be introduced into the conventional excitation force that is not restricted by the combination of the piezo element and one cantilever.

[0063] (2) Since the velocity can be directly measured by the heterodyne laser Doppler meter, the position is measured, and its derivative is obtained electrically to obtain a signal that is more resistant to noise than a device that obtains the velocity signal. Can be. In addition, it can be applied to a highly integrated cantilever array, and can perform optical scanning. In addition, liquid vibration is small, that is, noise can be reduced. (3) The feedback of the velocity term and the position term to the vibrator excited by the light enables the Q value control of the vibrator. Excitation of the target, vibration detection, and Q-value control are possible simply by irradiating light, which can contribute to improving the sensitivity of the vibrator-type sensor.

(4) Unlike the prior art, it is not necessary to apply a magnetic substance to a cantilever such as silicon, so a higher Q value can be expected.

(5) By optical scanning, Q value control can be applied to a large number of transducers immersed in a liquid, for example, to measure a large number of points in a cell.

[0067] (6) Since the velocity is directly measured by the heterodyne laser Doppler meter, the carrier frequency and the oscillation frequency of the heterodyne method can be greatly different, and high Q value control without oscillation can be performed. It becomes.

(7) By the feedback, a phase shift circuit having a flat frequency characteristic near the resonance frequency enables high Q value control without oscillation.

Industrial applicability

[0069] The method and apparatus for controlling the Q value of light excitation of an oscillator according to the present invention can be used for material identification, nanobiomechanics, and drug discovery by combining with a scanning microscope.

Claims

The scope of the claims

[1] In optical excitation, the Q value of the oscillator is apparently increased by feeding back the speed of the oscillator in the liquid directly measured by the speed measurement to the optical excitation device, and the sensitivity as the oscillator is enhanced. Oscillator light excitation Q-value control method.

[2] The method for controlling the optical excitation of a vibrator according to claim 1, wherein the vibrator is irradiated with excitation light and measurement light, and the return light of the measurement light of the vibrator is detected, whereby vibration in the liquid is detected. A method of controlling the Q value of optical excitation of a vibrator, which measures the speed of the vibrator.

[3] In optical excitation, by increasing the Q value of the vibrator apparently by feeding back the velocity directly measured by measuring the position and velocity of the vibrator in the liquid to the optical excitation device, and increasing the sensitivity of the vibrator A method of controlling the Q value of light excitation of a vibrator.

[4] The method for controlling the optical excitation of a vibrator according to claim 1, wherein the vibrator is irradiated with excitation light and measurement light, and the return light of the measurement light of the vibrator is detected, and the vibration in the liquid is detected. A method of controlling the Q value of optical excitation of a vibrator, characterized by measuring the speed directly measured by measuring the position and speed of the vibrator.

[5] The method for controlling the optical excitation Q value of a vibrator according to claim 1 or 3, wherein the liquid is water.

6. The method according to claim 1, wherein the liquid is ethanol. 4. The method according to claim 1, wherein the liquid is ethanol.

[7] The method for controlling the Q value of an oscillator according to claim 1 or 3, wherein the Q value control is applied to a number of oscillators immersed in a liquid by optical scanning. Optical excitation Q value control method.

[8] The method for controlling the Q value of light excitation of a vibrator according to the method for controlling the Q value of light excitation of a vibrator according to claim 7, wherein a large number of points in cells immersed in the liquid are measured.

[9] (a) a vibrator arranged in a liquid,

(b) a light entrance / exit section for entering / exiting excitation light and measurement light applied to the vibrator,

(c) a supply unit for excitation light and measurement light to the light entrance / exit unit,

(d) a speed detecting unit for directly detecting the speed of the vibrator by apparently increasing the Q value of the vibrator based on the return light of the measuring light of the light output / incident portion force. Light excitation Q value control device.

[10] The optical excitation Q-factor control device according to claim 9, wherein the speed detecting unit is also a heterodyne laser Doppler interferometer, and a band-pass filter, a phase shift circuit, and an amplifier are connected in series on the output side of the speed detecting unit. An optical excitation Q value control device, wherein the optical excitation Q value control device is connected to feed back to the excitation light supply unit.

[11] (a) a vibrator arranged in a liquid,

(d) a position / speed detector for apparently increasing the Q value of the vibrator based on the return light of the measurement light of the light output / incident force and detecting the position and speed of the vibrator. Optical excitation Q value control device.

12. The optical excitation Q-value control device according to claim 11, wherein the position 'speed detector is a heterodyne laser Doppler interferometer, and a bandpass filter and a phase shift circuit are provided on an output side of the position' speed detector. An optical excitation Q value control device, wherein an amplifier is connected in series and feedback is provided to the excitation light supply unit.

13. The optical excitation Q-value control device according to claim 11, wherein the speed detection unit is a heterodyne laser Doppler interferometer, and a superheterodyne circuit is connected to the heterodyne laser Doppler interferometer to output the excitation light. Optical excitation Q value control device characterized by feeding back to the supply unit.

[14] The optical excitation Q value control device according to claim 11, wherein the position / speed detection unit is

And a heterodyne laser Doppler interferometer, wherein a superheterodyne circuit is connected to the heterodyne laser Doppler interferometer to feed back the excitation light supply section.

15. The optically-excited Q-factor control device according to claim 9, wherein a flat phase shift circuit having a frequency characteristic near the resonance frequency is used by feedback.

16. The optically-excited Q-value control device according to claim 9, wherein the phase shift circuit is of a feedback type using CdS and LED cells. 10. The optical excitation Q-value control device according to claim 9, wherein the device controls a vibration characteristic of a cantilever of the scanning force microscope.