JP4632373B2 - Time-series conversion pulse spectrometer - Google Patents

Description

  The present invention relates to a time-series conversion pulse spectroscopic measurement apparatus, and more particularly to an arrangement structure (optical arrangement) of an optical system.

In recent years, with the practical application of ultra-short pulse laser technology, pulsed coherent far-infrared radiation (especially terahertz band) electromagnetic radiation technology and detection technology have made significant progress. As a result, time-series conversion pulse spectroscopy using this pulsed far-infrared electromagnetic wave has become possible, and the development of a practical device for time-series conversion pulse spectroscopy has been pioneered in Japan.

  Time-series conversion pulse spectroscopy is the measurement of the time-dependent electric field strength of a pulsed electromagnetic wave, and the time-dependent data (time-series data) is subjected to Fourier transform, whereby each frequency component forming the pulse is measured. This is a spectroscopic method for obtaining electric field strength and phase. One of the features of this spectroscopic method is that the measurement wavelength region is a boundary region between light and radio waves, which has conventionally been difficult to measure. Therefore, elucidation of the properties of new materials and new phenomena is expected by this spectroscopy. In addition, in the conventional spectroscopy, only the electric field strength of the electromagnetic wave was obtained, but in this time-series conversion pulse spectroscopic measurement method, since the time change of the electric field strength of the electromagnetic wave is directly measured, only the electric field strength (amplitude) of the electromagnetic wave is Not only that, it has the unique feature of being able to obtain its phase. Therefore, a phase shift spectrum can be obtained by comparing with the case where there is no sample. Since the phase shift is proportional to the wave vector, the dispersion relation in the sample can be determined using this spectroscopy, and the dielectric constant of the dielectric material can also be obtained from this dispersion relation (Japanese Patent Laid-Open No. 2005-259151). (See 2002-277394).

  FIG. 1 shows an example of a conventional time-series conversion pulse spectrometer.

  Reference numeral 1 denotes a light source that emits a femtosecond laser. The femtosecond laser light L1 emitted from the light source 1 is split by a beam splitter (splitting means) 2. One femtosecond laser is applied to the pulsed light emitting means 5 as excitation pulsed laser light (pump pulsed light) L2. At this time, the excitation pulse laser beam L2 is modulated by the optical chopper 3 and then condensed by the objective lens 4. The pulsed light radiating means 5 is, for example, a photoconductive element, and when the excitation pulse laser beam L2 is irradiated, a current flows instantaneously and radiates a far-infrared electromagnetic wave pulse. The far-infrared electromagnetic wave pulse is guided by the parabolic mirrors 6 and 7 and irradiated to the measurement sample 8. The reflected or transmitted pulsed electromagnetic wave (transmitted pulse electromagnetic wave in this example) of the sample 8 is guided to the detection means 12 by the parabolic mirrors 9 and 10.

  The other laser light split by the beam splitter 2 is guided to the detection means 12 as a detection pulse laser light (sampling pulse light) L3. This detection means 12 is also a photoconductive element, for example, which is irradiated with the detection pulse laser beam L3 and becomes conductive only at that moment, so that the electric field strength of the reflected or transmitted pulse electromagnetic wave from the sample 8 that has reached that moment is obtained. It can be detected as a current. The time-series signal of the electric field intensity of the reflected or transmitted pulsed electromagnetic wave from the sample 8 is obtained by using the optical delay means 13 (or 14) for the detection pulse laser light L3 for a predetermined time with respect to the excitation pulse laser light L2. It can be obtained by giving a delay time difference at intervals. In this example, in addition to the optical delay means 13 (or 14) for time series signal measurement, an optical delay means 14 (or 13) for time origin adjustment is also provided.

  Each time-resolved data of the electric field intensity of the reflected or transmitted pulse electromagnetic wave of the sample 8 is processed by the signal processing means. That is, it is transmitted to the computer 17 via the lock-in amplifier 16 and sequentially stored as time-series data, and the series of time-series data is subjected to Fourier transform processing by the computer 17 and converted to a frequency (frequency) space. Thus, the spectrum of the amplitude and phase of the electric field intensity of the reflected or transmitted pulse electromagnetic wave of the sample 8 is obtained.

JP 2003-131137 A JP 2003-121355 A JP2003-83888 JP 2003-75251 A JP2003-14620 JP 2002-277393 A JP 2002-277394 A JP 2002-257629 A JP 2002-243416 A JP 2002-98634 A JP 2001-141567 A JP 2001-66375 A Japanese Patent Laid-Open No. 2001-21503 JP 2001-275103 A Q. Wu and X.-C. Zhang, Appl. Phys. Lctt. 67 (1995) 3523) M. Tani, S. Matsuura, K .. Sakai, and S. Nakashima, Appl. 0pt. 36 (1997) 7553 Kiyomi Sakai: Spectroscopic Research, 50 (2001) 261 Seiji Kojima, Seiji Nishizawa, Mio Takeda: Spectroscopic Research, 52 (2003) 69

  As described above, in the time-series conversion pulse spectrometer, the far-infrared wavelength region, which was difficult with conventional spectrometers, is not only included in the spectrum measurement band, but not only intensity dispersion but also phase dispersion is included in the measurement spectrum. It can be measured independently. Furthermore, time-resolved spectroscopic measurement that tracks a transient phenomenon in the picosecond range in real time is also possible. Because of such characteristics, there are a wide variety of sample types and states (solid, liquid, gas, etc.) that can be measured by the time-series conversion pulse spectroscopic measurement device or that are desired to be measured. However, in order to perform time-series conversion spectroscopic measurement of such various samples and their states, different optical systems or optical arrangements are required according to them, which places a great burden on the user and changes the sample. There is a problem that it takes a long time to prepare for the start of subsequent measurement.

  Accordingly, the present invention has been made in view of the above circumstances, and provides a time-series conversion pulse spectroscopic measurement apparatus that can easily perform time-series conversion pulse spectroscopic measurement of various samples and their states in a short time. For the purpose.

In order to achieve the above object, the present invention employs the following configuration.
A time-series conversion pulse spectroscopic measurement apparatus as a reference example of the present invention includes a pulse laser light source, and a dividing unit that divides the pulse laser light from the pulse laser light source into excitation pulse laser light and detection pulse laser light, Pulsed light emitting means for emitting pulsed light including a wavelength in the far-infrared wavelength region by irradiation with the excitation pulsed laser, and reflected or transmitted pulsed light from the sample irradiated with the pulsed light from the pulsed light emitting means Detection means for detecting a time-series signal of electric field strength, a sample holder for holding the sample, and pulsed light reflected from or transmitted from the sample by the irradiation while guiding the pulsed light from the pulsed light emitting means side to the sample In the time-series conversion pulse spectroscopic measurement apparatus comprising the sample part entrance / exit optical system for guiding the light to the detecting means side, from the dividing means to the pulsed light emitting means An optical path length changing means for setting at least one photometric area disposed in an incident side optical path and / or a detection side optical path from the dividing means to the detecting means, and an incident side optical path from the dividing means to the pulsed light emitting means And / or at least one optical delay unit for measuring the time-series signal disposed in a detection-side optical path from the dividing unit to the detecting unit.

  Here, the “sample part entrance / exit optical system” means that before and after the sample (or the sample holding part) that requires replacement / adjustment of the optical system and / or change / adjustment of the optical arrangement when changing the type and state of the sample. An optical system including an optical system, which is an optical system disposed between the pulsed light emission means and the detection means.

  `` Optical path length changing means for photometric area setting '' means that the optical path length of the sample entrance / exit optical system changes due to, for example, replacement of the optical system and / or change of the optical arrangement accompanying a change in the type and state of the sample In addition, the measurement start position of the time series signal of the electric field strength of the reflected or transmitted pulse electromagnetic wave from the sample is set up to compensate for the change in the optical path length. Regarding the change, for example, it means a device having a configuration capable of compensating for a significant change in the optical path length only by scanning the reflector.

  The change of the optical path length by the optical path length changing means may be a configuration that can be changed continuously or a configuration that can be changed discontinuously. That is, for example, the configuration is such that the optical path length is continuously changed by scanning a reflector arranged in the optical path, or the optical path in which the photometric area is set for one sample is changed by the reflection mirror. It may be configured to switch to an optical path in which a photometric area is set for another sample.

  `` Optical delay means for measuring time series signals '' means that each optical delay means has the same function as the conventional optical delay means for measuring time series signals (symbol 13 or 14 in FIG. 1). However, in the case where a plurality of optical delay means are provided, it is different from the conventional optical delay means in that the time series signal can be measured over a longer time by the number of optical delay means. It is.

  It goes without saying that “optical length changing means for photometric area setting” and “optical delay means for measuring time-series signals” can be arranged in various ways regardless of parallel arrangement or series arrangement.

  According to the time-series conversion pulse spectroscopic measurement apparatus as a reference example of the present invention, when the optical path length of the sample entrance / exit optical system changes, the change in the optical path length is compensated for, and the reflected or transmitted pulse electromagnetic wave from the sample There is an effect that the measurement start position of the time series signal of the electric field strength can be set. In particular, even if the optical path length changes greatly due to the replacement of the optical system, the optical path length changing means for setting the measurement area can be used to compensate for the significant optical path length change. In addition, there is an effect that the photometric area can be set freely. When a plurality of optical delay means for measuring time series signals are provided, the time series signal can be measured over a longer time by the number of optical delay means.

  Further, in the time-series conversion pulse spectroscopic measurement apparatus as a reference example of the present invention, the optical path length changing means for setting the photometric area is a movable reflector.

  The “movable reflector for setting the photometric area” is typically a type of reflector whose optical path length can be changed by scanning. However, it is necessary to adjust the time origin required for adjusting the optical arrangement. The technical idea is completely different from the conventional reflector (symbol 13 or 14 in FIG. 1). That is, regarding a specific difference in configuration, the conventional time origin adjusting reflector is for adjusting the time origin shifted in the optical adjustment performed at the time of measurement. It was enough to have one because it could be short. Depending on the device, by providing the function of time origin adjustment to the “optical delay means for time series signal measurement”, there may be an independent time origin adjustment reflector. The reflector for time origin adjustment was not an essential component. On the other hand, the movable reflector for setting the photometric area as a reference example of the present invention is capable of compensating for even a significant change in the optical path length, so that one or more photometric areas can be set. The total scanning area of the movable reflectors for use is significantly wider than that of the reflector for adjusting the time origin. Further, by providing a larger number of reflectors, the scanning area can be further expanded. Therefore, as a reference example of the present invention, a movable reflector for setting a photometric area finds a completely different use method for a scanable reflector from the conventional one, and a wide variety of optical path lengths cannot be avoided. It can be said that it is meaningful that various samples can be easily measured only by scanning a reflector for setting a photometric area.

Furthermore, the “movable reflector for setting the photometric area” is a reflector of the reflector by arranging multiple reflectors in parallel when the scanning distance of one reflector cannot be increased due to size limitations. This is a configuration that can secure a longer optical path length by the number.
It should be noted that the “movable reflector for setting the photometric area” is not limited to the setting of the measurement start position of the time-series signal, but can be used for time origin adjustment, and various optical path length changes are required. This can be used to set the correct photometry area.

  The “movable reflector for setting the measurement area” is, for example, a reflector such as a corner cube mirror, but is not limited thereto.

  According to the time-series conversion pulse spectrometer as a reference example of the present invention, there is an effect that the optical path length can be continuously changed.

  In the time-series conversion pulse spectroscopic measurement apparatus as a reference example of the present invention, the optical path length changing means for setting the measurement area is a movable or fixed reflector, and any one of the reflectors includes the reflection Gate means for passing or blocking the pulsed light to the reflector on the incident side of the pulsed light to the reflector, and adding an optical path through one or more of the reflectors by switching the passing or blocking. It is possible to extend the optical path length and / or to shorten the optical path length by skipping one or more of the reflectors.

  The gate means is, for example, a reflection mirror. In this case, the optical path length is changed by switching the optical path of the pulsed light by inserting / removing the reflection mirror into / from the optical path. In other words, by inserting / removing the reflecting mirror, the pulsed light is incident on or blocked from a predetermined reflector, and an optical path through the reflector is added to extend the optical path length, or the reflector is skipped. Thus, the optical path length can be shortened.

  The gate means may be configured to pass and block pulsed light without moving spatially.

  Switching between the passage and blocking of the gate means may be either automatic or manual, and the optical path length may be changed by a plurality of gate means.

  According to the time-series conversion pulse spectrometer as a reference example of the present invention, there is an effect that the optical path length can be changed without spatially moving the reflector. That is, since the optical path length can be changed with only a fixed reflector, the apparatus can be manufactured at low cost. It is possible to select a reflector to be used from among a plurality of reflectors, and there is an effect that a free optical path can be set according to the measurement. Therefore, it is possible to select and measure a reflector to be used for each measurement of the same sample, not only for each replacement of the sample. In addition, for example, when one or more reflectors out of a plurality of reflectors are defective, it is possible to avoid the reflector and set the optical path. Further, the optical arrangement of the optical system related to the plurality of reflectors has an effect that various arrangements are possible.

  The time-series conversion pulse spectroscopic measurement apparatus as a reference example of the present invention is further characterized in that the passage or blocking of at least one of the gate means is performed by insertion into and removal from the optical path by translational movement of the gate means. To do.

  The gate means may be configured to translate with the reflector.

  The time-series conversion pulse spectroscopic measurement apparatus as a reference example of the present invention is further characterized in that the passage or blocking of at least one of the gate means is performed by insertion into and removal from the optical path by rotation of the gate means. To do.

  Here, “rotation” includes all cases where the optical path can be switched by the rotational movement of the gate means.

  The time-series conversion pulse spectroscopic measurement apparatus as a reference example of the present invention further includes a driving device that automatically scans the optical path length changing means and / or the optical delay means, and automatically controls the driving device. And a computer control device.

  Here, as the “driving device”, for example, a normal scanning driving device such as a stepping motor can be used, but is not limited thereto.

  According to the time-series conversion pulse spectroscopic measurement apparatus as a reference example of the present invention, the optical path length changing means and / or the optical delay means can be automatically scanned, and the scanning can be automatically controlled by a computer. Play.

  In addition, in the time-series conversion pulse spectroscopic measurement apparatus as a reference example of the present invention, the sample holder and the sample part entrance / exit optical system are provided in an attached optical unit that can be attached to and detached from the apparatus. It is characterized by that.

  Preferably, the attached optical unit is specially specialized with a sample portion entrance / exit optical system optimized for each sample.

  In this time-series conversion pulse spectroscopic measurement device, the size of the space on the device equipped with the attached optical unit is within a range in which the change of the optical path length can be corrected by the scanable reflector for setting the photometric area. Determined within. Therefore, for example, the dimensions of the space are 150 mm to 250 mm in width, 180 mm in depth, and 150 mm in height.

  According to the time-series conversion pulse spectroscopic measurement apparatus as a reference example of the present invention, a significant change in the optical path length accompanying the replacement of the attached optical unit can be compensated by the optical path length changing means for setting the photometric area. There is an effect that the preparation time until the start of measurement can be shortened. In addition, by using an exclusive optical unit specially designed with a sample part entrance / exit optical system optimized for each sample, there is no need to adjust the sample part entrance / exit optical system when replacing the attached optical unit. The effect of becoming.

  In addition, the time-series conversion pulse spectroscopic measurement apparatus as a reference example of the present invention is further characterized in that it is optically designed so as to have optical matching with the attached optical unit.

  Here, “having optical matching” means that FOV (Field of view) values match.

  According to the time-series conversion pulse spectroscopic measurement apparatus as the reference example of the present invention, it is possible to prevent the loss of light at the connection portion between the attached optical unit and the apparatus even by replacing the attached optical unit. .

The present invention also provides a pulse laser light source, a splitting means for splitting the pulse laser light from the pulse laser light source into an excitation pulse laser light and a detection pulse laser light, and a far red by irradiation with the excitation pulse laser. The pulse light emitting means for emitting pulsed light including a wavelength in the outer wavelength range, and the time series signal of the electric field intensity of the reflected or transmitted pulsed light from the sample irradiated with the pulsed light from the pulsed light emitting means are detected. Detecting means using pulse laser light for use, a sample holding part for holding the sample, and pulse light from the pulsed light radiating means side is guided to the sample and reflected or transmitted from the sample by the irradiation. in the stream conversion pulse spectrometer measurement device when and a sample section incoming and outgoing optical system for guiding to the detector side, and the sample holder and the sample unit input and output optical system Provided in the removable interchangeable in the supplied optical unit, over the accessory optical unit from said pulsed light emitting means, and / or, over a period from the detection means to the accessory optical unit, one or more plane mirrors, and one or more non-spherical mirrors Are arranged in this order.

The aspherical mirror disposed in the incident side optical path between the pulsed light emitting means and the sample part entrance / exit optical system condenses the pulsed light toward the sample. On the other hand, the plane mirror is disposed between the pulsed light radiating means and the aspherical mirror, and turns back the pulsed light emitted from the pulsed light radiating means. As a result, the optical path length between the pulsed light emitting means and the aspherical mirror can be increased. By making this optical path length long, the focal area collected by the aspherical mirror can be made as small as possible, and as a result, the spatial resolution of the sample to be measured can be improved.
Further, since the pulsed light is folded by the plane mirror, the apparatus can be configured to be extremely compact while taking a long optical path length.
In addition, since the optical path length between the pulsed light emitting means and the aspherical mirror can be increased, the distance between the aspherical mirror and the sample can be increased while maintaining a desired focal area. Thereby, the space around the sample, that is, the space for the sample portion entrance / exit optical system and the sample holding portion is sufficiently secured, so that the degree of freedom of analysis work can be increased.

  As for the detection side optical path between the detection means and the sample portion entrance / exit optical system, similarly to the incident side optical path, a plane mirror is arranged between the aspherical mirror and the detection means so that the optical path length is long. The focal area of the light beam collected by the aspherical mirror can be made as small as possible, and as a result, the spatial resolution of the sample to be measured can be improved. Further, like the incident side optical path, the apparatus can be configured compactly, and a sufficient space around the sample can be secured.

  FIG. 2 shows a schematic configuration of a time-series conversion pulse spectroscopic measurement apparatus according to the present invention and an optical path difference compensation mechanism for acquiring the time-series signal. Constituent elements similar to those in FIG.

The time-series conversion pulse spectroscopic measurement device 20 includes a pulse laser light source 1. The pulse laser light L1 from the pulse laser light source 1 is guided to a dividing means 2 that divides the pulse laser light L1 into an excitation pulse laser light L2 and a detection pulse laser light L3.
The time-series conversion pulse spectroscopic measurement device 20 further includes a pulsed light radiating unit 5 that emits pulsed light including a wavelength in the far-infrared wavelength region by irradiation with the excitation pulse laser L2, and a pulse from the pulsed light radiating unit 5 Detecting means 12 for detecting a time-series signal of the electric field intensity of the reflected pulsed light from the sample 8 irradiated with the light.
Between the pulsed light emitting means 5 and the detecting means 12, a sample holding part 31 for holding the sample 8, and sample part incident optical systems 32, 33 for guiding the pulsed light from the pulsed light emitting means side to the sample. 34, and sample part emission optical systems 35, 36, and 37 for guiding the pulsed light reflected from the sample by the irradiation to the detection means 12 side are provided.

Further, the time-series conversion pulse spectroscopic measurement device 20 includes at least one optical path length changing means for setting a photometric area (in the case of FIG. 2, a corner cube mirror) 41 and at least one optical delay means for measuring a time-series signal. 42 (corner cube mirror in the case of FIG. 2). Here, the optical path length changing means 41 is a movable reflector that can be scanned.
The optical path length changing means 41 for photometric area setting and the optical delay means 42 for measuring time-series signals are provided with a drive device (not shown) for automatically scanning, and this drive device is automatically controlled. A computer control device (not shown) is provided. (However, in the reflectors 41 and 42, the former may be used for time series signal measurement and the latter may be used for photometry area setting.)
Further, the sample holding unit 31 and the sample unit entrance / exit optical systems 32, 33, 34, 35, 36, and 37 are provided in the attached optical unit 30 that can be attached to and detached from this time-series conversion pulse spectrometer. .

  An elliptical mirror (aspherical mirror) 26 and a plane mirror 27 are installed as optical elements in the incident side optical path between the pulsed light emitting means 5 and the attached optical unit 30. The elliptical mirror 26 condenses the pulsed light from the pulsed light radiating means 5. The plane mirror 27 is disposed between the pulsed light radiating means 5 and the elliptical mirror 26, and fulfills the function of turning back the pulsed light from the pulsed light radiating means 5. The elliptical mirror 26 and the plane mirror 27 may be provided one by one as in the present embodiment, but a plurality of elliptical mirrors 26 and planar mirrors 27 may be used in combination.

  An elliptic mirror (aspherical mirror) 28 and a plane mirror 29 are installed as optical elements in the detection side optical path between the detection means 12 and the attached optical unit 30. The elliptical mirror 28 condenses the reflected pulsed light from the sample 8. The plane mirror 29 is disposed between the elliptical mirror 28 and the detection means 12, and fulfills the function of turning back the reflected pulse light from the elliptical mirror 28. The elliptical mirror 28 and the plane mirror 29 may be provided one by one as in the present embodiment, but may be used in combination.

The elliptical mirror 26, the plane mirror 27, the elliptical mirror 28, the plane mirror 29 and other optical systems (not shown) which are optical elements are optically designed so as to have optical alignment with the attached optical unit 30.
In the case of this embodiment, it is the structure which detects the time series signal of the electric field strength of the reflected pulsed light from a sample. Of course, it may be configured to detect a time-series signal of the electric field intensity of the transmitted pulsed light.

In the time-series conversion pulse spectroscopic measurement apparatus of the present invention having the above-described configuration, preparation for sample measurement is performed as follows.
First, the sample 8 to be measured is attached to the sample holder 31 in the attached optical unit 30. Next, the attached optical unit 30 is attached to the time-series conversion pulse spectrometer 20. Next, in order to set the origin of the time-series arrangement of the output signal with respect to the optical path length specific to the sample portion entrance / exit optical system 32, 33, 34, 35, 36, 37 in the attached optical unit 30, a drive (not shown) The apparatus and the computer control apparatus are operated to scan the reflector 41 for setting the photometric area. In this way, it completed the preparation of the sample measurement.
For sample measurement, the time-series conversion pulse spectroscopic measurement apparatus of the present invention operates substantially in the same manner as the conventional apparatus shown in FIG.

That is, the pulse laser light L1 emitted from the light source 1 is split by the splitting means 2 into an excitation pulse laser light (pump pulse light) L2 and a detection pulse laser light (sampling pulse light) L3.
The excitation pulse laser beam L2 is applied to the pulsed light emission means 5 through the lens 4. By this irradiation, the pulsed light radiation means 5 emits a far-infrared electromagnetic wave pulse. This far-infrared electromagnetic wave pulse is turned back by the plane mirror 27 and then guided to the elliptical mirror 26 and collected. The far-infrared electromagnetic wave pulse guided into the attached optical unit 30 is condensed via the sample portion incident optical systems 32, 33, and is applied to the sample 8. The reflected pulse electromagnetic wave reflected from the sample 8 including the optical information of the sample 8 is reflected by the elliptic mirror 28 outside the attached optical unit 30 through the sample portion incident optical systems 35, 36, and 37, and then the plane mirror. It is folded at 29 and further guided to the detection means 12.

On the other hand, the detection pulse laser light L3 divided by the dividing means 2 detects the electric field intensity of the reflected pulse electromagnetic wave from the sample 8 that has reached that moment, with the detecting means 12 being conductive only at that moment. It is possible. Here, the time series of the electric field intensity of the reflected pulse electromagnetic wave from the sample 8 by applying a delay time difference to the detection pulse laser light L3 by a predetermined time interval with respect to the excitation pulse laser light L2 by the reflector 42. A signal can be obtained.
Although not shown, this time-series conversion pulse spectroscopic measurement apparatus may include a reflector dedicated for adjusting the time origin.

As described above, according to the present embodiment, the pulsed light emitted from the pulsed light radiating means 5 is folded by the plane mirror 27 disposed between the pulsed light radiating means 5 and the elliptical mirror 26. As a result, the optical path length between the pulsed light radiating means 5 and the elliptical mirror 26 can be increased, and the focal area of the light beam collected by the elliptical mirror 26 can be made as small as possible. The spatial resolution of the sample 8 can be improved.
In addition, since the pulsed light is folded by the plane mirror 27, the apparatus can be configured to be extremely compact while taking a long optical path length.
Further, since the optical path length between the pulsed light radiating means 5 and the elliptical mirror 26 can be increased, the distance between the elliptical mirror 26 and the sample 8 can be increased while maintaining a desired focal area. As a result, a sufficient space for installing the attached optical unit 30 is ensured, and the analysis work can be facilitated.

  Like the incident side optical path, the detection side optical path between the detection means 12 and the attached optical unit 30 has a configuration in which a plane mirror 29 is disposed between the elliptical mirror 28 and the detection means 12 so as to increase the optical path length. The focal area of the light beam collected by the elliptical mirror 28 can be made as small as possible, and as a result, the spatial resolution of the sample 8 to be measured can be improved. Further, like the incident side optical path, the apparatus can be configured compactly, and a sufficient space for installing the attached optical unit 30 is secured.

  FIG. 3 (a) shows a schematic configuration of an optical path difference compensation mechanism for acquiring a time series signal as a reference example of the present invention.

  In this reference example, in the incident side optical path from the dividing means to the pulsed light emitting means and / or the detection side optical path from the dividing means to the detecting means, a plurality of optical path length changing means and / or optical delay means ( In the case of FIG. 3, the reflectors) are arranged to face each other in a state where the optical paths incident and reflected on the reflector are parallel and the optical paths are shifted. In the case of the figure, the reflector is a corner cube mirror. In this configuration, the pulsed laser light L2 or L3 incident on the scanning mechanism is sequentially reflected on the corner cube mirrors 51, 52, 53,... Sent to means 12.

  Due to such a configuration, the optical path length can be changed by the number of reflectors as compared with the case of one reflector. Also, with such a configuration, even when there is not enough space in the scanning direction of the reflector but there is sufficient space in the direction orthogonal to the scanning direction, it is possible to change the optical path length greatly. In this reference example, as shown in FIG. 3 (b), scanning mechanisms configured as shown in FIG. 3 (a) may be arranged in parallel in the incident side optical path and / or the detection side optical path.

  As shown in FIG. 3 (b), the optical path length changing means and / or the optical delay means configured as shown in FIG. 3 (a) may be arranged in parallel in the incident side optical path and / or the detection side optical path.

  FIG. 4 shows a schematic configuration of an optical path difference compensation mechanism for time series signal acquisition of a time series conversion pulse spectroscopic measurement apparatus as a reference example of the present invention.

  In this reference example, two reflectors (61 and 62 for the photometric area setting) (one corner cube mirror in the figure) and one for the time series signal measurement (corner cube mirror in the figure). And 63 and 64) are arranged side by side and configured to scan at the same time, and the reflectors 61 and 62 for setting the photometric area and the reflectors 63 and 64 for measuring the time series signal are arranged to face each other with the optical paths being shifted. Yes. In this configuration, the excitation pulse laser light L2 or the detection pulse laser light L3 divided by the dividing means 2 is reflected by the mirror 65, and then enters the scanning mechanism for photometry area setting and time series signal measurement. The light is sequentially reflected by the reflectors 63, 61, 64 and 62, guided to the outside of the scanning mechanism, further reflected by the mirrors 66 and 67, and sent to the pulsed light radiation means 5 or the detection means 12.

  Because of such a configuration, the optical path length can be changed twice as much as the scanning of the reflector as compared with the case of one corner cube mirror. Therefore, there is an effect that it is possible to quickly set a photometric area and time series signal measurement. The configuration of FIG. 4 may be used for either the optical path length changing means or the optical delay means.

  FIG. 5 (a) shows a schematic configuration of an optical path difference compensation mechanism for obtaining a time-series signal as a time-series conversion pulse spectrometer as a reference example of the present invention.

  In the reference example of FIG. 5 (a), the optical path length changing means 81, 82, 83,... For setting the measurement area are movable or fixed reflectors, and any one of the reflectors is at least the reflector. On the incident side of the pulsed light to the reflector, gate means 71, 73, 75 for passing or blocking the pulsed light to the reflector are provided, and one or two or more reflectors 81, 82 are switched by switching the passing or blocking. , 83,... Can be added to extend the optical path length, and / or one or more reflectors 81, 82, 83,... Can be skipped to shorten the optical path length. In the case of FIG. 5, the gate means is a reflecting mirror and includes reflecting mirrors 72, 74,... That reflect the pulsed light reflected from the reflectors 81, 82, 83,. . In this reference example, the passage / blocking of at least one reflecting mirror (gate means) is performed by inserting / removing the reflecting mirror into / from the optical path by rotating the reflecting mirror. In the figure, an arrow attached to the vicinity of the reflecting mirror, and a solid line and a dotted line indicating the reflecting mirror schematically show how the reflecting mirror is switched between passing and blocking.

  The operation of this reference example will be described with reference to FIG. 5 (b) in which a part of FIG. 5 (a) is enlarged. For example, before switching, when the reflecting mirror 71 is inserted in the optical path (solid line) and the reflecting mirror 72 (solid line) is removed from the optical path, the laser light L4 is reflected by the reflecting mirror 71. It becomes L41 and proceeds as L5. In this case, the reflector 81 is skipped. On the other hand, when the reflecting mirrors 71 and 72 are switched and the reflecting mirror 71 is removed from the optical path and the reflecting mirror 72 is inserted into the optical path as indicated by the dotted line, the laser beam L4 is reflected as L42. It is reflected at 81 to become L43, further reflected to become L44, reflected by the reflecting mirror 72, and proceeds as L5. Thus, the optical path length via the reflector 81 is added by switching. On the other hand, if this switching order is reversed, the optical path passing through the reflector 81 is eliminated and the optical path length is shortened. The configuration of FIG. 5 may be used for either the optical path length changing means or the optical delay means.

  FIG. 6 shows a schematic configuration of an optical path difference compensation mechanism for obtaining a time series signal of a time series conversion pulse spectroscopic measurement apparatus as a reference example of the present invention.

  In this reference example, a plurality of reflectors 101, 102,... Are arranged at appropriate positions according to applications, and the optical path length is determined by the gate means 91, 93,... And the reflectors 92, 94,. This is a configuration to be changed. In the case of FIG. 6, the gate means is a reflecting mirror.

  In this reference example, when the gate means 91, 93, ... and the reflecting mirrors 92, 94, ... sent to the adjacent reflectors are arranged at the positions of the solid lines, the pulse light incident on the optical path length changing means is The light is reflected by the gate means 91, passes by the reflecting mirror 92, the gate means 93, and the reflecting mirror 94, is reflected by the reflecting mirror 95, and is guided to the outside. In this case, the measurement of the sample using the reflectors 101 and 102 is not performed. On the other hand, by switching the gate means 91 and the reflecting mirror 92 to the position of the dotted line, the pulsed light can be measured on the sample using the reflector 101 (reflection measurement in the figure). Furthermore, by switching the gate means 91 and the reflecting mirror 92 to the position of the solid line, and further switching the gate means 93 and the reflecting mirror 94 to the position of the dotted line, measurement of the sample using the reflector 102 (in the figure, gas cell measurement) Is possible.

  7 (a) and 7 (b) show a schematic configuration of an optical path difference compensation mechanism for obtaining a time series signal of a time series conversion pulse spectrometer side device as a reference example of the present invention.

  In this reference example, the passage or blocking of at least one gate means 112 is performed by inserting / removing the gate means 112 into / from the optical path by translational movement. Particularly in the case of FIG. 7, both the gate means 112 and the reflector 115 are mounted on the moving device 116. Further, the moving device 116 is also equipped with a reflecting mirror 113 that reflects and sends the pulsed light reflected from the reflector 115 to the reflecting mirror 114. In the case of the figure, the gate means 112 is a reflecting mirror.

  In this case, when the moving device 116 is disposed at the position of FIG. 7A, the pulsed light reflected from the reflecting mirror 111 passes by the gate means 112 and the reflecting mirror 113 and passes through the reflecting mirror 114. Are reflected and guided to the outside. When the moving device 116 is moved from the position of FIG. 7 (a) to the position of FIG. 7 (b), the gate means 112 and the reflecting mirror 113 and the reflector 115 are both translated and the optical path passing through the reflector 115. Is added to extend the optical path length, and measurement using the reflector 115 becomes possible.

It is a schematic block diagram of the conventional time series conversion pulse spectroscopy apparatus. It is a schematic block diagram of one Embodiment of the time series conversion pulse spectroscopy apparatus of this invention. (a) It is a schematic block diagram of the optical path difference compensation mechanism for time series signal acquisition of the time series conversion pulse spectrometer as a reference example of the present invention. It is a figure which shows the structure which has arrange | positioned the structure shown to (b) and (a) in parallel. It is a schematic block diagram of the optical path difference compensation mechanism for time-series signal acquisition as a time-series conversion pulse spectrometer as a reference example of the present invention. (a) It is a schematic block diagram of the optical path difference compensation mechanism for time series signal acquisition as a time series conversion pulse spectrometer as a reference example of the present invention. (b) It is a partial enlarged view of (a). It is a schematic block diagram of the optical path difference compensation mechanism for time series signal acquisition of the time series conversion pulse spectroscopy apparatus as a reference example of the present invention. (a) It is a schematic block diagram of the optical path difference compensation mechanism for time series signal acquisition of the time series conversion pulse spectrometer as a reference example of the present invention. (b) It is a figure which shows the case where the gate means and reflector of (a) are moved.

Explanation of symbols

1 Pulse laser source
2 Dividing means
8 samples
12 Detection means
20 Time-series conversion pulse spectrometer
26,28 Aspherical mirror
27,29 plane mirror
30 Attached optical unit
31 Sample holder
32,33,34 Specimen entrance optical system
35, 36 sample portions emitting optical system
41, 42 Optical path length changing means or optical delay means
51,52,53 reflector
61,62,63,64 reflector
71,73,75 Gate means
81,82,83 reflector
91,93 Gate means
101,102 reflector
112 Gate means
115 reflector

Claims (1)

A pulsed laser light source;
A dividing means for dividing the pulse laser beam from the pulse laser light source into a pulse laser beam for excitation and a pulse laser beam for detection;
Pulsed light emitting means for emitting pulsed light including a wavelength in the far-infrared wavelength region by irradiation with the excitation pulsed laser;
Detecting means for detecting a time series signal of the electric field intensity of the reflected or transmitted pulsed light from the sample irradiated with the pulsed light from the pulsed light emitting means using the pulsed laser light for detection;
A sample holder for holding the sample;
Time-series conversion comprising: a sample portion entrance / exit optical system that guides the pulsed light from the pulsed light emitting means side to the sample and guides the pulsed light reflected or transmitted from the sample to the detecting means side by the irradiation In the pulse spectrometer,
The sample holder and the sample portion entrance / exit optical system are provided in an attachable / detachable accessory optical unit,
One or more plane mirrors and one or more aspherical mirrors are arranged in this order from the pulsed light emitting means to the attached optical unit and / or from the detecting means to the attached optical unit. A time-series conversion pulse spectroscopic measurement device.

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