EP3400488A2 - Device for imaging the electromagnetic field of a sample - Google Patents
Device for imaging the electromagnetic field of a sampleInfo
- Publication number
- EP3400488A2 EP3400488A2 EP17711703.3A EP17711703A EP3400488A2 EP 3400488 A2 EP3400488 A2 EP 3400488A2 EP 17711703 A EP17711703 A EP 17711703A EP 3400488 A2 EP3400488 A2 EP 3400488A2
- Authority
- EP
- European Patent Office
- Prior art keywords
- sample
- channel
- beams
- optical
- frequency
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
- 230000005672 electromagnetic field Effects 0.000 title claims abstract description 24
- 238000003384 imaging method Methods 0.000 title description 3
- 230000003287 optical effect Effects 0.000 claims abstract description 50
- 238000001514 detection method Methods 0.000 claims abstract description 28
- 238000006073 displacement reaction Methods 0.000 claims description 15
- 230000001360 synchronised effect Effects 0.000 claims description 8
- 238000000034 method Methods 0.000 claims description 5
- 238000012512 characterization method Methods 0.000 claims description 3
- 230000001902 propagating effect Effects 0.000 claims description 3
- 239000000523 sample Substances 0.000 description 120
- 239000000835 fiber Substances 0.000 description 4
- 238000005259 measurement Methods 0.000 description 4
- 230000002123 temporal effect Effects 0.000 description 3
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 2
- 239000000654 additive Substances 0.000 description 2
- 230000000996 additive effect Effects 0.000 description 2
- 238000009792 diffusion process Methods 0.000 description 2
- 238000001093 holography Methods 0.000 description 2
- 238000002347 injection Methods 0.000 description 2
- 239000007924 injection Substances 0.000 description 2
- 230000002452 interceptive effect Effects 0.000 description 2
- 239000011159 matrix material Substances 0.000 description 2
- 239000004065 semiconductor Substances 0.000 description 2
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 1
- 230000003321 amplification Effects 0.000 description 1
- 238000003491 array Methods 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 230000000903 blocking effect Effects 0.000 description 1
- 230000014509 gene expression Effects 0.000 description 1
- 230000003116 impacting effect Effects 0.000 description 1
- 238000004651 near-field scanning optical microscopy Methods 0.000 description 1
- 238000003199 nucleic acid amplification method Methods 0.000 description 1
- 239000013307 optical fiber Substances 0.000 description 1
- 230000010349 pulsation Effects 0.000 description 1
- 230000005855 radiation Effects 0.000 description 1
- 229910052710 silicon Inorganic materials 0.000 description 1
- 239000010703 silicon Substances 0.000 description 1
- 239000000377 silicon dioxide Substances 0.000 description 1
- 230000003595 spectral effect Effects 0.000 description 1
- 239000000758 substrate Substances 0.000 description 1
Classifications
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B9/00—Measuring instruments characterised by the use of optical techniques
- G01B9/02—Interferometers
- G01B9/02001—Interferometers characterised by controlling or generating intrinsic radiation properties
- G01B9/02002—Interferometers characterised by controlling or generating intrinsic radiation properties using two or more frequencies
- G01B9/02003—Interferometers characterised by controlling or generating intrinsic radiation properties using two or more frequencies using beat frequencies
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B9/00—Measuring instruments characterised by the use of optical techniques
- G01B9/02—Interferometers
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B9/00—Measuring instruments characterised by the use of optical techniques
- G01B9/02—Interferometers
- G01B9/02041—Interferometers characterised by particular imaging or detection techniques
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01Q—SCANNING-PROBE TECHNIQUES OR APPARATUS; APPLICATIONS OF SCANNING-PROBE TECHNIQUES, e.g. SCANNING PROBE MICROSCOPY [SPM]
- G01Q30/00—Auxiliary means serving to assist or improve the scanning probe techniques or apparatus, e.g. display or data processing devices
- G01Q30/02—Non-SPM analysing devices, e.g. SEM [Scanning Electron Microscope], spectrometer or optical microscope
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R29/00—Arrangements for measuring or indicating electric quantities not covered by groups G01R19/00 - G01R27/00
- G01R29/08—Measuring electromagnetic field characteristics
- G01R29/0864—Measuring electromagnetic field characteristics characterised by constructional or functional features
- G01R29/0892—Details related to signal analysis or treatment; presenting results, e.g. displays; measuring specific signal features other than field strength, e.g. polarisation, field modes, phase, envelope, maximum value
-
- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03H—HOLOGRAPHIC PROCESSES OR APPARATUS
- G03H1/00—Holographic processes or apparatus using light, infrared or ultraviolet waves for obtaining holograms or for obtaining an image from them; Details peculiar thereto
- G03H1/04—Processes or apparatus for producing holograms
- G03H1/0443—Digital holography, i.e. recording holograms with digital recording means
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01Q—SCANNING-PROBE TECHNIQUES OR APPARATUS; APPLICATIONS OF SCANNING-PROBE TECHNIQUES, e.g. SCANNING PROBE MICROSCOPY [SPM]
- G01Q60/00—Particular types of SPM [Scanning Probe Microscopy] or microscopes; Essential components thereof
- G01Q60/24—AFM [Atomic Force Microscopy] or apparatus therefor, e.g. AFM probes
- G01Q60/38—Probes, their manufacture, or their related instrumentation, e.g. holders
-
- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03H—HOLOGRAPHIC PROCESSES OR APPARATUS
- G03H1/00—Holographic processes or apparatus using light, infrared or ultraviolet waves for obtaining holograms or for obtaining an image from them; Details peculiar thereto
- G03H1/04—Processes or apparatus for producing holograms
- G03H1/0443—Digital holography, i.e. recording holograms with digital recording means
- G03H2001/0463—Frequency heterodyne, i.e. one beam is frequency shifted
-
- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03H—HOLOGRAPHIC PROCESSES OR APPARATUS
- G03H1/00—Holographic processes or apparatus using light, infrared or ultraviolet waves for obtaining holograms or for obtaining an image from them; Details peculiar thereto
- G03H1/04—Processes or apparatus for producing holograms
- G03H1/0465—Particular recording light; Beam shape or geometry
- G03H2001/0469—Object light being reflected by the object
-
- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03H—HOLOGRAPHIC PROCESSES OR APPARATUS
- G03H1/00—Holographic processes or apparatus using light, infrared or ultraviolet waves for obtaining holograms or for obtaining an image from them; Details peculiar thereto
- G03H1/04—Processes or apparatus for producing holograms
- G03H1/0465—Particular recording light; Beam shape or geometry
- G03H2001/0471—Object light being transmitted through the object, e.g. illumination through living cells
-
- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03H—HOLOGRAPHIC PROCESSES OR APPARATUS
- G03H2223/00—Optical components
- G03H2223/12—Amplitude mask, e.g. diaphragm, Louver filter
Definitions
- the present invention relates to imaging devices of the electromagnetic field present near the surface of a sample.
- the invention relates to an optical detection device for amplitude and phase characterization of the electromagnetic field of an area of a sample, the device comprising a light source adapted to emit a light beam whose electromagnetic field has a pulse C, a means adapted to divide the beam into a first beam defining a first channel, said reference channel and a second beam defining a second channel called sample channel, a modulation system that shifts the frequency of the electromagnetic fields of the two beams of a frequency ⁇ , a beam coupler adapted to collect the beams coming from the two channels, an optical detection system adapted to detect the signal resulting from the interference between the beams coming from the two channels and coupled via said beam coupler.
- Such a device requires the use of a matrix detector which limits the range of wavelengths in which the measurements can be made.
- the spatial resolution of such a device is moreover limited by the wavelength used.
- the present invention is intended to overcome these disadvantages.
- a device of the kind in question is characterized in that the sample is placed in the sample channel, the optical detection system comprises an optical detector and a device adapted to measure the amplitude and signal phase, an opaque screen comprising an optical aperture is placed at the level of the area in the sample channel, close to the sample.
- the characterization of the field in amplitude and in phase can be obtained with a spatial resolution which will depend only on the size of the optical aperture and which will be independent of the wavelength.
- Such a device may be used over an extended spectral range.
- the amplitude of the signal can be amplified by such a device which will be particularly interesting in the case of a signal of low amplitude interest.
- the light source is the sample itself, and the sample is also the means adapted to separate the beam;
- the means adapted to separate the beam and the sample are three distinct elements, said second sample channel comprising the sample;
- the means adapted to separate the beam is a beam splitter;
- the device adapted to measure the amplitude and the phase of the signal is a synchronous detection device;
- the modulation system comprises a first modulation means, one or the other of said first reference channel or of said second sample channel comprises said first modulation means, said first modulation means being adapted to frequency modulate the field of said modulation means; first beam or second beam respectively, the first modulation means being adapted to implement the frequency shift ⁇ between the respective frequencies of the fields corresponding to the beams of each of the two channels;
- the modulation system comprises a first modulation means, said first reference channel comprises said first modulation means, said first modulation means being adapted to frequency modulate the field of the first beam, and also a second modulation means, said second channel; sample comprising said second modulation means, said second modulation means being adapted to frequency modulate the field of the second beam, the first and second modulation means being adapted to implement the frequency shift ⁇ between the respective frequencies of the fields corresponding to the beams each of the two lanes;
- said second modulation means precedes the sample in the order of progression of the beam of the sample channel
- the sample and the optical aperture of the opaque screen are adapted to be displaced relative to each other;
- the sample is mounted on a system of displacement adapted to move the sample relative to the fixed optical aperture;
- the displacement system is a piezo ⁇ electrical system
- the optical aperture is an empty area of the opaque screen
- the optical aperture is an area of the transparent opaque screen at the frequency ⁇ / 2 ⁇ €;
- the device is geometrically arranged so that the second beam passes through the sample and the opaque screen in any order, as it travels to the collection system, the device being geometrically arranged so that the first and second beams can be collected at the beam coupler;
- the device is geometrically arranged so that the second beam is reflected on the surface of the sample and passes through the opaque screen in any order before moving towards the collection system, the device being geometrically arranged so that the first and the second beam can be collected at the beam coupler;
- the optical detector is a single-channel detector
- the optical aperture is installed at the end of the tip of the cantilever of an atomic force microscope.
- the invention also relates to an optical detection method for characterizing in amplitude and in phase the electromagnetic field of a zone of a sample, said method comprising the following steps of emitting a light beam whose electromagnetic field has a pulsation C , to divide the beam into a first beam defining a first path, said reference path and a second beam defining a second path called path sample, to place on the sample path a sample and an opaque screen comprising an optical aperture placed at the level of the zone near the sample, to shift in frequency the electromagnetic fields of the two beams of a frequency ⁇ , to collect the beams from the two channels, to detect the signal resulting from the interference between the beams from the two channels and coupled via said beam coupler, to deduce the amplitude and the phase of the electromagnetic field of a sample zone.
- FIG. 1a illustrates the principle of the invention
- FIG. 1b illustrates the case where the device is integrated in an AFM tip
- FIG. 2 illustrates the first embodiment of the invention
- FIG. 3 illustrates the second embodiment of the invention
- FIG. 4 illustrates the third embodiment of the invention
- FIG. 5 illustrates the fourth embodiment of the invention
- FIG. 6 illustrates the fifth embodiment of the invention
- FIG. 7 illustrates a practical embodiment
- an incident light beam is separated into two light beams traveling in two different ways 70, 80, the two signals being out of phase by a known frequency, only one of the two signals impacting the sample 1 to be imaged .
- the sample is placed in the sample channel 70.
- the sample 1, carried by a sample holder 30, is compared with an opaque screen 2 of size greater than the wavelength and comprising an optical aperture 20, said screen effectively blocking light around the optical aperture, only light passing through the optical aperture reaching the detection system.
- the signals coming from the two channels then interfere and the interference signal is detected by a detection system 50 adapted to deduce from the interference signal the image of the amplitude and the phase of the electromagnetic field present near the zone.
- the sample 1 and the opaque screen 2 move relative to each other so that different areas of the sample 1 are successively placed next to each other. with the optical aperture 20 of the opaque screen 2 and imaged.
- the spatial selection of the area to be imaged by the optical aperture 20 in the opaque screen 2 makes it possible to spatially resolve the image of the sample 1, that is to say to identify the area of the sample 1 to which the measured amplitude and phase must be attributed.
- This may be for example the displacement of the sample holder 30 relative to the fixed screen 2 or the displacement of the screen 2 relative to the fixed sample holder. In all that follow will be considered that the screen 2 is fixed and the sample holder 30 moves the sample 1 (the sample holder is the displacement system 3).
- the opaque screen 2 may be placed before or after the sample 1 in the order of progression of the second beam of the second sample channel 70.
- the sample 1 is placed before the screen 2 in the order of progression of the second beam.
- the second beam and the opening should be at least roughly aligned, especially if the beam is narrow.
- the incident light beam is separated into two channels 70, 80 by means adapted to divide the beam 91.
- a modulation system 78 implements a frequency shift ⁇ (temporal beat at the frequency ⁇ between the two paths) between the fields of the beams which traverse each channel.
- the modulation system 78 comprises for example modulation means 7, 8 positioned on each of the channels 70, 80 respectively. These modulation means 7, 8 implement a frequency shift ⁇ (temporal beat at the frequency ⁇ between the two paths) between the fields of the beams that traverse each channel.
- ⁇ temporary beat at the frequency ⁇ between the two paths
- the field in the sample channel 70 is for example of the form:
- the field in the reference channel is for example of the form: £ e t (() + 27T /) t + ⁇ p k /)
- E ref 1 With E ref 1 'amplitude of the field in the reference channel 80 and (ref the phase of the field in the reference channel 80.
- the heterodyne detection consists in interfering on the optical detector 5 the light beam of interest which has impacted the sample with a second light beam which circulates in the reference channel, then in determining the amplitude and the phase with the help of an oscilloscope or slow acquisition systems.
- the intensity I at the output of the detector 5 therefore corresponds to the interference of these two signals and has the form:
- the amplitude R is proportional to the amplitude of the detected field that passes through the sample 1 and the phase c is equal to an additive constant, (- q> re f + is), where is is a constant, at the phase ⁇ eC h of the studied field.
- the screen pierced with an optical aperture is for example a cantilever with an optical aperture.
- amplitude and phase can be obtained in multiplying the signal to be analyzed by a known signal of the same frequency, for example using an oscilloscope or a sufficiently fast digital analog converter.
- the modulation system 78 may comprise only a first modulation means 8.
- One or the other of said first reference channel 80 or of said second sample channel 70 comprises said first modulation means 8, said first modulating means 8 being adapted to frequency modulate the field of said first beam or second beam respectively.
- the first modulation means 8 is adapted to implement the frequency shift ⁇ between the respective frequencies of the fields corresponding to the beams of each of the two channels.
- the opaque screen 2 comprising the opening 20 can be moved relative to the sample 1 to select an area to be imaged.
- a displacement system 3 allows a relative displacement of the sample 1 with respect to the opaque screen 2.
- Collection systems 40 make it possible to collect the light beams on either side of the opaque screen 2. For example, sample 1 is moved and aperture 20 and beam in sample channel 70 are aligned.
- the opening 20 will have a dimension that is substantially smaller than the size of the beam that illuminates the sample 1.
- the displacement makes it possible to access the spatial variations of the amplitude and phase parameters of the electromagnetic field with a resolution that depends only on the size of the aperture 20 and not on the wavelength.
- the means adapted to divide the beam 91 may be a beam splitter through which the light beam coming from the source. Mirrors positioned on the path of the light beam can be used to orient the beams of each of the channels.
- the modulation means used 7, 8 can be modulators and in particular acousto-optic modulators, but also other types of modulators such as modulators in phase amplitudes or Mach-Zehnder.
- the frequency f is, for example, 80 MegaHertz (MHz) and the frequency offset is, for example, 1 KiloHertz (kHz).
- Collection systems can be placed on the path of the light beam in the sample path 70, the collection systems being adapted to give a direction to the dispersed beam before it passes through the sample, or at the exit of the opening 20 in the sample channel 70. its trajectory towards the detector.
- the source may for example be a laser source.
- the collection systems are, for example, lenses 40.
- the detector is for example a photodiode or for example a single-channel detector.
- the light beams coming from the two channels 70 and 80 can be recombined via a beam coupler 92.
- the sample 1 is moving relative to the opaque screen 2 comprising an opening 20, via a displacement system 3 on which is installed sample 1 (this is the sample holder 30).
- the translation system is for example a piezoelectric system.
- the translation system may be a system of translation plates equipped with electric motors, in particular for applications at long wavelengths such as microwave applications.
- the opening 20 in the opaque screen has such a diameter D incpt, it may be a hole or a transparent or translucent area in the frequency of the electromagnetic field of interest.
- the opaque screen is for example a pierced beam an opening. The opening may be smaller than the wavelength, for example.
- the opening may for example be installed at the end of the tip 200 of the cantilever 2 of an atomic force microscope (AFM) as shown in Figure lb.
- the opening is made by crossing both the tip 200 and the cantilever 2, so that the light located at the end of the tip 200 can pass through the tip 200 and the cantilever 2 from one side.
- This technique can be coupled with a local scanning probe technique 31 in the case of an AFM cantilever, for example.
- the scanning tip in the near field zone to the surface of the sample gives access to super-resolved images of the amplitude and phase of the near field at the surface of the sample.
- the intensity of the beam of interest can be very low because the light must pass through an opening smaller than its wavelength.
- Heterodyne measurement will play an important role in amplifying the optical beam of interest.
- the heterodyne amplification consists of interfering on the optical detector via the beam coupler 92 the beam of interest, of very low intensity, with the reference beam of much greater intensity.
- said second modulation means 7 precedes the sample 1 in the order of progression of the beam of the sample channel 70.
- the device 10 is mounted in free space.
- the laser 9 emits a light beam which is separated by the beam splitter 91 into two light beams corresponding to the two channels:
- the reference channel 80 in which the beam passes through a first modulator 8, which modulates the field of the beam passing through it at the frequency f, then is reflected by a first mirror 81 in the direction of the beam coupler 92,
- the sample channel 70 comprising a second mirror 71, the beam being reflected by said second mirror 71 to then pass through the second modulator 7, which modulates the field of the beam at the frequency f + ⁇ , the beam then passing through a first collection system 41, then the beam passes through the sample 1, the beam having a direction substantially perpendicular to the direction in which the sample 1 extends, the beam from the opening 20 of the opaque screen facing the sample passing through a second collection system 40 to be collected by the beam coupler 92,
- the detected signal is transmitted to the synchronous detection device 6 which is adapted to extract the phase ⁇ and the module R according to the physical principle of the heterodyne detection explained above.
- the path of the beam arriving at the sample 1 and leaving the opening 20 of the opaque screen is in free space.
- the opaque screen comprising an opening 2 can be placed "before" the sample, ie the beam coming from the modulator 7 passes first through the opaque screen comprising the opening 20 before crossing. the sample.
- the system operates with a translucent sample.
- the displacement system 3 must be at least partially translucent also to allow the beam to pass.
- the device 10 is in a partially fiberized version, that is to say that the architecture of the device 10 is similar to the previous embodiment, but a part of the light beams in each channel are transmitted by cables.
- the path of the beam arriving at the sample 1 and leaving the opening 20 of the opaque screen is in free space.
- the opaque screen comprising an opening 20 can be placed "before" the sample, ie the beam coming from the modulator 7 passes first through the opaque screen comprising the opening 20 before crossing. the sample.
- the system operates with a translucent sample.
- the displacement system 3 must be at least partially translucent also to allow the beam to pass.
- the source 9 emits a light beam which is separated by the beam splitter 91 into two light beams corresponding to the two channels:
- the reference channel 80 in which the beam passes through a first modulator 8, which modulates the field of the beam passing through it at the frequency f, then is reflected by a first mirror 81 in the direction of the second beam splitter 92,
- the sample channel 70 comprising a second mirror 71, the beam being reflected by said second mirror 71 to then pass through the second modulator 7, which modulates the field of the beam at the frequency f + ⁇ , the beam being then again reflected by a third mirror 72, the beam thus reflected having a direction substantially parallel to the direction of extension of the sample 1 (oblique incidence of the beam, the electromagnetic field diffuse at the opening 20 therethrough), the beam passing through then a first collection system 41 then the sample 1 to be partially transmitted in the direction substantially perpendicular to the sample 1 and partially reflected by the sample 1, the beam from the opening 20 of the opaque screen 2 in the sample then passing through a second collection system 40 to be collected by the beam coupler 92.
- the detected signal is transmitted to the synchronous detection device 6 which is adapted to extract the phase ⁇ and the module R according to the principle of the heterodyne detection explained ci - above.
- Such a configuration may notably appear in the case of integrated waveguide, the field being then only a surface field and the injection being made laterally at the inlet of the guide.
- the system operates with a translucent sample.
- the displacement system 3 must be at least partially translucent also to allow the beam to pass.
- the path of the beam arriving at the sample 1 and leaving the opening 20 of the opaque screen is in free space.
- the laser 9 emits a light beam which is separated by the beam splitter 91 into two corresponding light beams. to both ways:
- the reference channel 80 in which the beam passes through a first acousto-optic modulator 8, which modulates the field of the beam passing through it at the frequency f, then is guided towards the beam coupler 92,
- sample 1 said beam being reflected by the sample, the reflected beam being collected by the second beam splitter 73, and in a beam directly transmitted to the beam coupler 92, the set of beams from the second splitter beam 73 being collected by the beam coupler 92.
- collection systems 40, 41, 42 can be used to collect the beam in its path, including a collection system 41 for its arrival on the mirror 72, a collection system 40 for its passage between the second beam splitter 73 and sample 1 and a collection system 42 for its path out of the second beam splitter 73.
- the detected signal is transmitted to the device 6 adapted to extract the phase ⁇ and the module R, according to the heterodyne detection principle explained above. This is for example a synchronous detection device.
- the system operates in retro-reflected mode, that is to say that it operates in particular on an opaque sample.
- the path of the beam arriving at the sample 1 and leaving the opening 20 of the opaque screen is in free space.
- the incident beam on the sample could also have an oblique incidence on the sample 1.
- the light source 9 is the sample 1 itself, and the sample 1 is also the means adapted to separate the beam 91.
- the sample 1 may for example be a semiconductor laser, and is then a source of radiation.
- the semiconductor laser emits a propagating field at its end in the so-called reference channel 80 and the electromagnetic field is measured at its surface in the so-called sample channel 70.
- the path of the beam arriving at the sample 1 and leaving the opening 20 of the opaque screen is in free space.
- FIG. 7 illustrates a practical embodiment of the invention adapted to the study of the amplitude and the phase of the field on the surface of a passive waveguide, the injection of which is done laterally by means of a micro-lentillant fiber.
- the device 10 comprises a SNOM microscope comprising a piezoelectric plate and a cantilever aperture probe 17.
- a tunable laser source 9 emits a monochromatic beam of wavelength arbitrarily set between 1490 nm and 1650 nm, coupled in a monomode fiber 11.
- a fibered coupler 90 makes it possible to separate the beam into two paths, the sample channel 70 and the reference channel 80.
- a fiber-optic acousto-optic modulator present on each channel 7, 8 makes it possible to induce a temporal beat between the two frequency channels.
- a micro-lentillant fiber 12 is connected to the sample channel, as beam collection system, so as to focus the beam in the sample inlet that is to say the passive waveguide 13.
- the guide 13 is placed on the piezoelectric plate 14 which acts as a displacement system.
- This signal transmitted in free space above the nano-aperture is collected by a high numerical aperture objective and then focused on an optical fiber 16, recombined with the reference channel using a second fibered coupler 93.
- the result signal is then sent to a fiber detector 5 where the reference field and the field that passes through the sample transmitted by the nano-aperture interfere.
- the voltage delivered by the detector is then demodulated using a synchronous detection at the frequency ⁇ , to obtain an amplitude proportional to the amplitude of the field probed by the scanning probe and a phase equal to an additive constant near the phase of this probed field.
- the waveguide is for example a silica guide on a silicon substrate of transverse dimensions less than the wavelength (cross section 200 ⁇ 500 nm 2 ).
- phase c which is accessed in addition to the amplitude measurement provides information on the optical path and simultaneously provides information on the index of the medium and the distance traveled.
- measurements of amplitude R and phase ⁇ allow access to the sample diffusion matrix connecting the input and output modes of the electromagnetic field.
- the phase ⁇ may also reveal information on the nature of the oscillator (plasmonic or cavities).
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- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Health & Medical Sciences (AREA)
- General Health & Medical Sciences (AREA)
- Nuclear Medicine, Radiotherapy & Molecular Imaging (AREA)
- Radiology & Medical Imaging (AREA)
- Engineering & Computer Science (AREA)
- Computing Systems (AREA)
- Theoretical Computer Science (AREA)
- Electromagnetism (AREA)
- Investigating Or Analysing Materials By Optical Means (AREA)
Abstract
Description
Claims
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
FR1650165A FR3046683B1 (en) | 2016-01-08 | 2016-01-08 | DEVICE FOR IMAGING THE ELECTROMAGNETIC FIELDS OF A SAMPLE |
PCT/FR2017/050041 WO2017118828A2 (en) | 2016-01-08 | 2017-01-06 | Device for imaging the electromagnetic field of a sample |
Publications (1)
Publication Number | Publication Date |
---|---|
EP3400488A2 true EP3400488A2 (en) | 2018-11-14 |
Family
ID=56069028
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
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EP17711703.3A Withdrawn EP3400488A2 (en) | 2016-01-08 | 2017-01-06 | Device for imaging the electromagnetic field of a sample |
Country Status (5)
Country | Link |
---|---|
US (1) | US10684113B2 (en) |
EP (1) | EP3400488A2 (en) |
JP (1) | JP7141948B2 (en) |
FR (1) | FR3046683B1 (en) |
WO (1) | WO2017118828A2 (en) |
Family Cites Families (6)
Publication number | Priority date | Publication date | Assignee | Title |
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JP3009199B2 (en) * | 1990-09-28 | 2000-02-14 | 株式会社日立製作所 | Photoacoustic signal detection method and apparatus |
JPH08262038A (en) * | 1995-03-20 | 1996-10-11 | Nikon Corp | Microopening probe and manufacture of microopening probe |
JPH11316240A (en) * | 1998-05-01 | 1999-11-16 | Olympus Optical Co Ltd | Scanning near-field optical microscope |
FR2792082B1 (en) * | 1999-04-06 | 2003-05-30 | Thomson Csf | DIGITAL HOLOGRAPHY DEVICE |
JP4117348B2 (en) * | 1999-08-19 | 2008-07-16 | 独立行政法人産業技術総合研究所 | Near-field probe and method for making near-field probe |
JP2003009199A (en) * | 2001-06-19 | 2003-01-10 | Toshiba Corp | Telephone system and telephone terminal |
-
2016
- 2016-01-08 FR FR1650165A patent/FR3046683B1/en active Active
-
2017
- 2017-01-06 WO PCT/FR2017/050041 patent/WO2017118828A2/en active Application Filing
- 2017-01-06 JP JP2018535414A patent/JP7141948B2/en active Active
- 2017-01-06 EP EP17711703.3A patent/EP3400488A2/en not_active Withdrawn
- 2017-01-06 US US16/068,639 patent/US10684113B2/en active Active
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US20190041185A1 (en) | 2019-02-07 |
FR3046683A1 (en) | 2017-07-14 |
WO2017118828A3 (en) | 2017-10-05 |
FR3046683B1 (en) | 2018-06-29 |
JP7141948B2 (en) | 2022-09-26 |
WO2017118828A2 (en) | 2017-07-13 |
US10684113B2 (en) | 2020-06-16 |
JP2019501394A (en) | 2019-01-17 |
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