JP2002257759A - Method and device for measuring of time-resolved electron spin resonance - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately measure only a weak time-resolved electron spin resonance(ESR) signal of several % or less of a dynamic dielectric constant variation signal by effectively removing transit dielectric constant variation caused by a dynamic carrier or others. SOLUTION: Two sets of sample chambers comprising a sample and a cavity resonator are used, one sample chamber (a main sample chamber) is placed inside a magnetic field, and the other sample chamber (a reference sample chamber) is placed outside the magnetic field. A time-resolved ESR signal is generated in only the main sample chamber and a dynamic carrier signal is generated in both of the main sample chamber and the reference sample chamber. A microwave divided from a single microwave source irradiates both sample chambers. By synthesizing the microwave signal passed through the sample chamber by shifting the phase of the microwave by 180 degrees, the microwave signal is effectively converted into a differential signal in a microwave level. Only the time-resolved ESR signal is mainly contained in the signal after being synthesized.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method and an apparatus for measuring time-resolved electron spin resonance. The present invention evaluates semiconductors and optical semiconductors, evaluates photocatalytic substances and their reaction efficiencies, studies the reaction mechanism of photocatalytic substances, evaluates magnetic substances, evaluates substances exhibiting a super-water-repellent effect, evaluates cosmetic materials,
It is effective when applied to evaluation of paint substances such as pigments.

[0002]

2. Description of the Related Art Electron Spin Resona
nce: ESR, also known as electron paramagnetic resonance (Electron Parama)
Gnetic Resonance (EPR) is a spectroscopic measurement method that detects paramagnetic and ferromagnetic species, such as free radicals and magnetic substances, and obtains information on their electronic state and structure. ing. Applications of ESR include detection of free radicals and active oxygen in medical science and biochemistry, detection of short-lived species generated by photoexcitation, high-sensitivity detection of defects in solids, detection of subsequent defects and impurities in semiconductors It is used for detailed research on organic and inorganic magnetic materials.

[0003] The principle of ESR is that a sample is placed in a magnetic field of a suitable intensity (typically 100-1000 mT), and a proper frequency (typically several hundred MHz to several tens GHz).
Is absorbed in the sample, and the fluctuation of the electromagnetic wave absorption due to the Zeeman effect with respect to the magnetic field strength (magnetic flux density) is recorded and detected. What this detects is:
Electron spin (paramagnetic) species generated in a substance can be summarized, but free radicals, magnetic substances, lattice defects in solids,
It is possible to detect a broken chemical bond (dangling bond).

[0004] At present, the most typical ESR apparatus includes, as basic components, a microwave source, a resonator for measurement, an electromagnet (for sweeping a magnetic field), a detector, a Q-curve observing apparatus, and the like. Among these, the measurement resonator (typically a cavity resonator,
A loop gap resonator or the like is used for the purpose of amplifying microwave absorption. As an external additional circuit, for example, a magnetic field modulation device and a modulation detection circuit, an automatic frequency control circuit, a homodyne detection circuit, and the like are added as needed for the purpose of increasing the S / N.

On the other hand, there is a time-resolved ESR method as a measuring method using this ESR apparatus. Here, "time-resolved" means that a signal at that point in time is measured for a radical species that is transiently present after performing instantaneous excitation. Since many of the above paramagnetic species have many short lifetimes, while the short-lived paramagnetic species generated by excitation using a pulse laser or the like does not disappear (between several hundred ns and several ms). This is a method for high-speed detection with a storage oscilloscope or the like. Time-resolved ESR is an advantageous method for measuring short-lived paramagnetic substances generated by pulsed light. In this case, the magnetic field modulation device and the modulation detection circuit cannot be used.

In principle, the signal detected by the ESR apparatus includes not only the electron spin resonance absorption but also a change in the dielectric constant of the sample when the signal changes. Usually,
The signal detected by sweeping the magnetic field is understood as electron spin resonance absorption. The time-resolved ESR is measured by greatly amplifying a signal from a short-lived paramagnetic substance generated by pulsed light, and at the same time, when a large dielectric constant change occurs in a sample (referred to as a dynamic dielectric constant change in this specification). Has the disadvantage that this unwanted signal is also greatly amplified at the same time. Dynamic dielectric constant changes are often caused by the movement of dynamic carriers (electrons, holes, and their aggregates), which are precursors of short-lived paramagnetic species. This problem often occurs with samples. Photocatalytic substances represented by titanium oxide, etc.
Various solid states such as a crystalline state and the size of fine particles have been produced, and it is known that a slight difference is caused in the reactivity as a catalyst. That is, it is a condition that a photocatalyst having good performance has a high reactivity. Among them, titanium oxide is a material of UV care products for cosmetics,
Or it is an important industrial product as a raw material for white paint,
When used in these applications, those that are stable and have low reactivity are preferred so as not to cause adverse reactions to the skin. Therefore, conversely, a measure has been taken to suppress the reaction by adsorbing a stabilizer that eliminates surface radicals.

[0007] However, there are few examples of assay methods that directly link the production method with the reactivity of surface radicals, and that help guide the production of better performing materials. At present, in addition to directly analyzing the product and evaluating the performance as a catalyst, surface radicals generated by irradiating steady light are detected by steady ESR. Can only capture radicals. In addition, ESR detection is also performed by converting a radical on the surface into another stable radical by a spin trap method. However, since this is an indirect method, information obtained is limited. An example of a method using short-lived surface radicals directly related to the reaction as an evaluation method is not known.

In addition, ESR is already used for measuring defects in semiconductor materials such as silicon, because a broken bond or an impurity center may be detected as a radical center. In particular, since ESR has high detection sensitivity, it has sufficient sensitivity to be used in a method for assaying these defects. Further, in silicon and the like, it is used for examining the crystalline state, and is used for grasping each state of crystal, polycrystal, and amorphous. A cavity resonator capable of directly measuring a semiconductor wafer is also commercially available.

[0009]

Many important solid samples to be measured for time-resolved ESR, such as photocatalysts and optical semiconductors, generate single-life paramagnetic species and generate dynamic carriers at the same time. It has the characteristic that the permittivity changes (dynamic permittivity change). The signal of the change in the dielectric constant is time-resolved E
In many cases, the signals overlap with the signal strength of the SR signal or much larger than that of the SR signal, and it is impossible to perform the time-resolved ESR measurement in these systems. According to the present invention, in a time-resolved ESR measurement, a transient dielectric constant change due to a dynamic carrier or the like is effectively removed, and only a weak time-resolved ESR signal of several percent or less of a dynamic dielectric constant change signal is accurately measured. It is an object to provide a method and an apparatus.

[0010]

The principle of the present invention is schematically shown in FIG. 1 in comparison with the conventional principle of ESR measurement. In the present invention, the sample chamber including the sample and the cavity
One set of sample chambers (main sample chamber) is placed in a magnetic field, and the other (reference sample chamber) is placed outside the magnetic field. In principle, the time-resolved ESR signal is generated only in the main sample chamber, and the dynamic permittivity change signal is generated in both the main sample chamber and the reference sample chamber. The two sample chambers are irradiated with microwaves split from a single microwave source. Then, the microwave signal after passing through the sample chamber is synthesized by shifting the phase of the microwave by 180 degrees, thereby effectively converting it into a difference signal at a microwave level. The synthesized signal mainly contains only the time-resolved ESR signal.

That is, in the conventional method (in the lower frame of FIG. 1),
The obtained signal is {(ESR signal) + (dielectric constant change signal)}, whereas in the present invention (upper in FIG. 1), (signal obtained from main sample chamber) = {(ESR signal) + (dielectric) Based on the fact that the rate change signal) 試 料, (the signal obtained from the reference sample chamber) = (the dielectric constant change signal), as the measurement signal, ｛(the signal obtained from the main sample chamber) − (the signal obtained from the reference sample chamber) Signal) = (ESR signal)}.

The advantages of the synthesis at the microwave level are as follows. Since a microwave generated from a single microwave source is used, an off-the-shelf ESR microwave unit including a normal homodyne detection circuit or the like can be used as it is. In addition, since the dynamic permittivity change signal is erased at the microwave level, it is possible to use a microwave preamplifier after erasing to increase the signal accuracy without saturating, and to use an electrical preamplifier used after the detector. It is also possible to increase the signal amplification by increasing the amplification factor.

In order to effectively remove the dynamic permittivity change signal generated from the two sample chambers, it is desirable to make the experimental conditions of the two sample chambers as equal as possible. in this case,
The following adjustments and considerations are required. (1) Prepare two measurement samples equivalent in sample amount, sample tube, dewar for temperature adjustment, cryostat, etc. (2) Match the resonant microwave frequencies of the cavity resonator including the sample as much as possible. (3) Match the resonance rates (Q values) of the cavity resonator including the sample as much as possible. (4) The microwave intensity to be introduced into the sample should be matched as much as possible. (5) Adjusting the intensity of the laser light to be introduced.

A specific method for making the two sample chambers equivalent will be described. First, two measurement samples equivalent to a sample amount, a sample tube, a dewar for temperature adjustment, a cryostat, and the like are mounted in the two sample chambers. For each of the sample chambers, a microwave response curve (showing an absorption curve called Q-dip) is first measured using a device mounted on a normal ESR device. If the resonance frequencies are different, a dielectric material such as a quartz rod or a Teflon (registered trademark) tube is inserted into the sample chamber to make the resonance frequencies match. Next, the phase of the reflected microwave signal is relatively set to 18
After shifting by 0 degrees, the intensity of the irradiated microwaves is further adjusted and combined so as to obtain a flat curve without Q-dip. Next, a pulse laser (Q switch pulse YA
G laser or excimer laser is desirable)
The sample is irradiated with the pulsed laser beam from the sample, and the transient signal is recorded with a transient oscilloscope or the like. By adjusting the intensity of the pulse laser beam, the condition is set such that the dynamic permittivity change signal is canceled out by the synthesis and becomes the smallest.

In the automatic frequency control (AFC) device, which is usually performed using the resonance frequency characteristics of the sample chamber, most of the reflected microwaves from the two sample chambers are eliminated by this method. The effect is higher when the cavity resonator for adjustment is provided. In this case, the measurement signal overlaps the unnecessary modulation signal generated due to the difference between the resonance frequency of the adjustment cavity resonator and the resonance frequency of the measurement sample chamber. Therefore, the AFC modulation is stopped during the time-resolved ESR measurement. It is desirable to add a circuit that performs this.

In the time-resolved ESR measurement according to the present invention, a photocatalytic substance or a semiconductor substance can be measured. In the measurement of the photocatalyst substance, a photocatalyst substance such as titanium oxide or a photocatalyst substance to which a reactant is adsorbed or bonded is used for measurement as a solid. In some cases, it is measured at low temperature such as liquid nitrogen temperature, liquid helium temperature, etc.
Adjust the lifetime and relaxation time of the intermediate to a measurable range.
Pulse laser light (most preferably Q switch Y) of a wavelength that can act as a photocatalyst (in the case of titanium oxide, near ultraviolet light having a wavelength shorter than 350 nm is preferable).
(Using an AG laser, an excimer laser, or the like) and the measurement is performed by the method of the present invention. Time-resolved ESR can identify short-lived intermediates, such as surface radicals of photocatalytic substances or radicals formed by reacting reactants on the surface. It is possible. That is, from the linearity of the time-resolved ESR signal, the type of radical species, the position of the broken bond, and the localization state can be determined.
You can know their lifespan and chemical reaction process. This makes it possible to evaluate the performance as a photocatalyst substance and select a substance that easily reacts. On the other hand, when the same substance is used as a cosmetic material or a pigment, it is preferable to select a substance that does not easily react.

In measuring semiconductor materials such as gallium arsenide, silicon, germanium, and gallium indium arsenide, a pulse laser having a sufficiently short wavelength capable of inter-band excitation is used. If necessary, liquid nitrogen temperature or liquid helium temperature is used to adjust the relaxation time and life of the intermediate. Carriers generated by photoexcitation are captured at defect levels, and the generated paramagnetism (isolated spin) can be detected by this measurement. That is, when defects and impurities are present, they become E
The SR signal appears. Since the solid has many defects and low crystallinity generates a large amount of isolated spins, the solid crystallinity,
The defect amount can be evaluated. The same high-sensitivity measurement is possible even in the ground state that is not originally photoexcited, but the amount of defects is small and the sensitivity is relatively low as compared with the method according to the present invention. In the method of the present invention, the isolated spin species captured by the trap level existing between the band gaps, which is not seen in the ordinary ground state measurement, becomes a new measurement target, so that the measurement sensitivity is improved by increasing the isolated spin species. In addition, there is an advantage that the influence of a defect in the operating state of the semiconductor in which carriers and the like are generated by optical excitation can be grasped.

The time-resolved electron spin resonance measuring method and the time-resolved electron spin resonance apparatus of the present invention based on the above are as follows. (1) A first sample inserted into a first cavity resonator arranged in a magnetic field and a second sample equivalent to the first sample inserted into a second cavity resonator arranged outside the magnetic field Simultaneously irradiating the sample with pulsed light while irradiating the sample with microwaves; and a first method of reflecting and returning from the first cavity resonator.
Taking the difference between the microwave signal of the sample and the second microwave signal reflected and returned from the second cavity resonator. A time-resolved electron spin resonance measurement method, wherein only a spin resonance signal is extracted.

(2) In the time-resolved electron spin resonance method according to (1), the first microwave signal reflected from the first cavity resonator and fed back and the first microwave signal reflected from the second cavity resonator are reflected. Taking the difference between the returning second microwave signal and the second microwave signal;
A time-resolved electron spin resonance method characterized in that a difference is obtained by synthesizing the microwave signal and the microwave signal with a phase shift of 180 degrees.

(3) Adjusting the cavity resonators so that the resonance frequencies of the two cavity resonators into which the same sample is inserted coincide with each other, and the phases of the reflected microwave signals from the two cavity resonators And the relative intensity of the microwaves introduced into the two cavity resonators is adjusted so that the combined signal obtained by combining the reflected microwaves from the two cavity resonators becomes substantially zero. Step 2) irradiating the sample in the two cavity resonators simultaneously with the pulsed light so that the combined signal becomes substantially zero.
Adjusting the intensity ratio of the pulse light applied to the sample in the two cavity resonators, and simultaneously applying the pulse light to the sample in the two cavity resonators while applying a magnetic field to only one of the two cavity resonators. Irradiating and using said synthesized signal as a detection signal to detect a time-resolved electron spin resonance signal.

(4) A magnetic field generator, a microwave source,
A first cavity resonator located in a magnetic field generated by the magnetic field generator and into which a sample is inserted; a second cavity resonator located outside the magnetic field generated by the magnetic field generator and into which a sample is inserted; A first microwave circuit for guiding microwaves generated from the microwave source to the first and second cavity resonators and a microwave reflected from the first and second cavity resonators are combined. A second microwave circuit, a detector for detecting the microwave combined by the second microwave circuit, and a relative position of the microwave guided to the first cavity resonator and the microwave guided to the second cavity resonator. To adjust the relative phase of the microwave reflected from the phase shifter and / or the first and second cavity resonators provided in the first microwave circuit for adjusting the phase. Provided in the second microwave circuit of A phase shifter, and an attenuator provided in the first microwave circuit for adjusting a relative intensity of microwaves guided to the first cavity resonator and the second cavity resonator; A pulse light source; and light splitting means for splitting the pulse light from the pulse light source and simultaneously irradiating the sample in the first cavity resonator and the sample in the second cavity resonator. Time-resolved electron spin resonance apparatus. According to this apparatus, by taking the difference between the microwave signals reflected and returned from the two cavity resonators, the dynamic signal change due to the change in the dielectric constant of the sample can be eliminated, and only the electron spin resonance signal can be extracted. .

(5) In the time-resolved electron spin resonance apparatus according to (4), the light splitting means is configured to irradiate the sample with the light intensity applied to the sample in the first cavity resonator and the sample in the second cavity resonator. 1. A time-resolved electron spin resonance apparatus comprising means for adjusting a ratio of light intensity applied to a substrate. According to the present invention, it becomes possible to perform time-resolved ESR measurement on a functional material such as a photocatalyst and an optical semiconductor having a large dynamic dielectric constant change and a sample containing the same. Since the time-resolved ESR method is a method for measuring short-lived radicals directly related to the reactivity of the photocatalyst, the present invention also provides the most effective assay method for assaying photocatalytic substances.

[0023]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 2 shows an example of a microwave circuit of the ESR device according to the present invention. Microwave unit of ready-made ESR measuring device (combines microwave source and detector)
10, the demultiplexing circuit 20 and the external AFC device 3
0 was attached. The microwave output from the microwave outlet of the microwave unit 10 is divided into two in the circulator C0 of the branching circuit 20, and the circulators C1, C2
To the two cavity resonators CV1 and CV2, and the reflected waves are synthesized again in the circulator C0. An external magnetic field is applied by an electromagnet to only one of the two cavity resonators CV1. Attenuators AT1, AT2, phase shifters PS1, PS2, and shutters SH1, SH2 are provided between the two paths.
The phase and intensity of the microwave can be adjusted independently through two paths. Further, unnecessary microwave reflected waves are removed by the single tubes D1 and D2. The synthesized signal is returned to the microwave inlet of the microwave unit 10 again through the circulator C0.

According to this circuit configuration, even when a homodyne detection circuit is provided in the ready-made microwave unit 10, the microwave unit can be used as it is. Further, a preamplifier for amplifying microwaves can be provided in front of the detector as needed. The Q-curve measurement oscilloscope 40 for performing the adjustment is ES
What was previously equipped in the R measuring device was used. The sample lasers S1 and S2 in the two cavity resonators CV1 and CV2 are irradiated with excitation laser pulse light from the pulse laser 50. While changing the external magnetic field with the magnetic field sweeping device 60, a signal synchronized with the trigger signal from the pulse laser is recorded and integrated on the transient oscilloscope 70, and the signal processing device 8
0 and the data was processed and accumulated. A personal computer was used as the signal processing device 80.

Next, an adjustment method for making the two sample chambers equivalent will be described with reference to a change in the resonance curve of the cavity resonator shown in FIG. In addition, (1) and (2) of the following operations are operations performed by a normal ESR device. (3)
(7) are operations newly added in the present invention. Note that the following operations (1) to (7) are desirably performed without applying a magnetic field to the cavity resonator CV1 and the sample S1. (1) With the samples S1 and S2 mounted on the cavity resonators CV1 and CV2, the microwave circuits are appropriately opened and closed by the switches SH1 and SH2, and the resonance curves of the sample chamber are independently controlled by the oscilloscope 40 for Q-curve measurement. To be measured. (2) Adjust each cavity so that the reflection from each sample chamber becomes zero when there is no ESR signal. (3) Match the resonance frequencies of the two sample chambers. At this time, a dielectric such as a quartz rod is inserted into the cavity resonator for an appropriate length (resonance frequency adjustment: [A] in FIG. 3).

(4) The signals reflected from the two sample chambers and returned are shifted by 180 degrees in phase. When a homodyne circuit is provided, the signal from the main sample chamber is shifted by 0 degrees and the signal from the reference sample chamber is shifted by 180 degrees with respect to the Ref signal (inverting the phase: [B in FIG. ]). (5) Further, the intensities of the microwaves introduced into the two sample chambers are adjusted by the attenuators AT1 and AT2 so that the two signals cancel each other (microwave power adjustment: [C] in FIG. 3). (6) Adjust the frequency of the external AFC circuit 30 to the resonance frequency of the sample chamber. (7) The samples S1 and S2 are irradiated with laser light from the pulse laser 50 to observe carrier signals. The optical path is adjusted so that both signals are maximized independently. Further, the light intensity ratio is adjusted so that the carrier signal is canceled and minimized.

FIG. 4 is a schematic diagram of a laser light distribution optical system for adjusting the intensity of the excitation light pulse sent to the two sample chambers.
By rotating the half-wave plate HWP mounted on the rotary stage RS to rotate the linear polarization direction of the laser light and passing the polarized light through the polarizing prism P, the intensity of the laser beam divided into two is continuously measured. The light amount ratio can be adjusted. The three mirrors M1
The sample is distributed to the main sample chamber and the reference sample chamber using M3.

FIG. 5 shows the result of eliminating the dynamic dielectric constant change of titanium oxide (P25 manufactured by Degussa) at room temperature. The amount of light is adjusted by rotating the half-wave plate HWP shown in FIG. The dynamic permittivity change signal generated in the main sample chamber was recorded as a positive signal, and the dynamic permittivity change signal generated in the reference sample chamber was recorded as a negative signal. Only by adjusting the light intensity
When the intensity of the dynamic permittivity change signal (line A) generated in the 00% main sample chamber and the intensity of the dynamic permittivity change signal (line B) generated in the 100% reference sample chamber are equal, almost dynamic as shown in line C is obtained. The dielectric constant change signal can be erased. Assuming that the signal intensity depends only on the light distribution ratio, the signal peak value is theoretically expressed by the following equation with respect to an arbitrary rotation angle θ.

[0029]

(Equation 1)

Here, I _Main is the signal intensity of the main sample chamber, I _Main
Ref is the signal intensity of the reference sample chamber and I ₀ is the total laser energy. The change in signal strength was in good agreement with this equation. Therefore, it is theoretically proved that the dynamic permittivity change signal can always be eliminated by adjusting the rotation angle of the HWP. As a result of the experiment, it was found that although a residual signal due to a slight linear shift was observed, the dynamic permittivity change signal could always be reduced to 5% or less as compared with the case of a single sample chamber.

Next, using a titanium oxide powder as a sample, the sample was repeatedly excited by a laser pulse of 10 Hz from a nanosecond YAG laser, and the time change of the obtained signal was recorded by a transient oscilloscope. External magnetic field is about 320mT
The measurement was performed 200 times for each point at 10 Hz using 201 points from to about 340 mT as measurement points, and time-resolved signals up to 50 microseconds after laser excitation were integrated on an oscilloscope. From this result, FIG. 6 shows a time-resolved ESR spectrum in which a signal observed at 9 microseconds after excitation is plotted with respect to a change in magnetic field.

In FIG. 6, the upward direction on the vertical axis indicates microwave emission, and the downward direction indicates microwave absorption. The appearance of this emission or absorption peak means that the target surface radical or the radical species generated near the surface gives a time-resolved electron spin resonance signal 9 μs after excitation, and the presence of any of these radical species Is shown.
The total amplitude of the signal in this measurement is about 1% of the maximum amplitude of the dynamic permittivity change signal in FIG. 5, and measurement of such a weak time-resolved ESR signal is newly enabled. On the other hand, the distinction between absorption and emission gives information on the mechanism of the involved chemical reaction. This measurement and its analysis enable detection and quantification of short-lived intermediates of the chemical reaction on the surface of the photocatalytic substance, thereby enabling an evaluation directly related to the function of the photocatalytic substance.

First of all, the present invention realizes:
This is a direct evaluation of the reactivity of a photocatalytic substance represented by titanium oxide. In the process of producing crystals and powders, a method can be provided which can be used as a numerical value and used for direct evaluation of its catalytic ability. This method can be diverted as a method for evaluating the stability of a pigment substance and the safety of a cosmetic carrier using the same substance. This evaluation method can be directly linked to the development and processing of high-performance materials. Second, it is possible to newly generate a short-lived lattice defect (mainly a trap level existing between band gaps) which is not present in the ground state and measure the semiconductor substance. Thereby, the amount of lattice defects and the crystal state of the solid can be evaluated.

[0034]

According to the present invention, a time-resolved ESR measurement of a functional material having a large dynamic dielectric constant change, such as a photocatalyst or an optical semiconductor, by effectively removing a transient dielectric constant change due to dynamic carriers or the like. Becomes possible.

[Brief description of the drawings]

FIG. 1 is a diagram showing a principle diagram of the present invention.

FIG. 2 is a diagram showing an example of a microwave circuit of the ESR device according to the present invention.

FIG. 3 is an explanatory diagram of an adjustment method for making two sample chambers equivalent.

FIG. 4 is a schematic diagram of a laser light distribution optical system that adjusts the intensity of an excitation light pulse sent to two sample chambers.

FIG. 5 is a diagram showing a removal state of a dynamic permittivity change signal.

FIG. 6 is a diagram showing a measurement example of a time-resolved ESR signal.

[Explanation of symbols]

10: microwave unit, 20: demultiplexing circuit, 30: external AFC device, 40: oscilloscope for Q curve measurement,
50: pulse laser, 60: magnetic field sweeping device, 70: transient oscilloscope, 80: signal processing device, C0
C2: circulator, PS1, PS2: phase shifter (phase shifter), AT1, AT24: attenuator (attenuator), SH1, SH2: shutter, D1, D2: single-row tube, CV1, CV2: cavity (cavity resonator) , S
1, S2: sample, HWP: 波長 wavelength plate, RS: rotary stage, P: polarizing prism, M1 to M3: mirror

Claims (5)

[The claims] A first sample inserted into a first cavity placed in a magnetic field and a first sample inserted into a second cavity placed outside the magnetic field; Irradiating the second sample with pulsed light while simultaneously irradiating the microwave; and a first microwave signal reflected from the first cavity resonator and returned, and reflected from the second cavity resonator. Taking the difference from the second microwave signal to be fed back, and removing only the electron spin resonance signal by eliminating the dynamic signal change due to the change in the dielectric constant of the sample. Resonance measurement method. 2. The time-resolved electron spin resonance method according to claim 1, wherein the first microwave signal is reflected from the first cavity and returns, and the first microwave signal is reflected from the second cavity and returned. The step of obtaining a difference between the first microwave signal and the second microwave signal is performed by synthesizing the first microwave signal and the second microwave signal by shifting the phase by 180 degrees, thereby obtaining a difference. Time-resolved electron spin resonance method. 3. Adjusting the cavity resonators so that the resonance frequencies of the two cavity resonators into which equivalent samples are inserted coincide with each other; and adjusting the phases of the reflected microwave signals from the two cavity resonators. A step of relatively shifting by 180 degrees; and a step of adjusting the relative intensity of the microwaves introduced into the two cavity resonators so that a combined signal obtained by combining the reflected microwaves from the two cavity resonators becomes substantially zero. Adjusting the intensity ratio of the pulsed light applied to the samples in the two cavity resonators so that the combined signal becomes substantially zero when the sample in the two cavity resonators is simultaneously irradiated with the pulsed light. In a state where a magnetic field is applied to only one of the two cavity resonators, the sample in the two cavity resonators is simultaneously irradiated with pulsed light, and the synthesized signal is used as a detection signal to detect time-resolved electron spins. Time-resolved electron spin resonance measurement method which comprises the steps of detecting a signal. 4. A magnetic field generator, a microwave source, a first cavity resonator which is located in a magnetic field generated by the magnetic field generator and into which a sample is inserted, and located outside the magnetic field generated by the magnetic field generator. A second cavity into which a sample is inserted, and a microwave generated from the microwave source,
A first microwave circuit leading to the second cavity resonator; a second microwave circuit combining microwaves reflected from the first and second cavity resonators; and the second microwave circuit. A detector for detecting microwaves combined by a wave circuit; and a first microwave for adjusting a relative phase of microwaves guided to the first cavity resonator and the second cavity resonator. A phase shifter provided in the circuit and / or a shifter provided in the second microwave circuit for adjusting the relative phase of microwaves reflected from the first and second cavity resonators. A phaser; an attenuator provided in the first microwave circuit for adjusting a relative intensity of microwaves guided to the first cavity resonator and the second cavity resonator; And dividing the pulse light from the pulse light source Time-resolved electron spin resonance apparatus, comprising a beam splitting means for simultaneously irradiating the sample of the first cavity and the sample in the resonator second cavity. 5. The time-resolved electron spin resonance apparatus according to claim 4, wherein said light splitting means controls the light intensity applied to the sample in said first cavity resonator and the light intensity applied to the sample in said second cavity resonator. A time-resolved electron spin resonance apparatus comprising means for adjusting a ratio of irradiation light intensity.