KR101730445B1 - optical-phase imaging system - Google Patents

optical-phase imaging system Download PDF

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Publication number
KR101730445B1
KR101730445B1 KR1020150179241A KR20150179241A KR101730445B1 KR 101730445 B1 KR101730445 B1 KR 101730445B1 KR 1020150179241 A KR1020150179241 A KR 1020150179241A KR 20150179241 A KR20150179241 A KR 20150179241A KR 101730445 B1 KR101730445 B1 KR 101730445B1
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South Korea
Prior art keywords
light
optical
output
light source
unit
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KR1020150179241A
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Korean (ko)
Inventor
정동호
정은주
박정욱
홍진표
강호주
정현미
김성훈
김진아
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엠투테크 주식회사
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
    • G01J9/00—Measuring optical phase difference; Determining degree of coherence; Measuring optical wavelength
    • G01J9/02—Measuring optical phase difference; Determining degree of coherence; Measuring optical wavelength by interferometric methods
    • G01J9/0246—Measuring optical wavelength
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
    • G02B27/10—Beam splitting or combining systems
    • G02B27/1006—Beam splitting or combining systems for splitting or combining different wavelengths
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/24—Coupling light guides
    • G02B6/26—Optical coupling means
    • G02B6/27—Optical coupling means with polarisation selective and adjusting means
    • G02B6/2746—Optical coupling means with polarisation selective and adjusting means comprising non-reciprocal devices, e.g. isolators, FRM, circulators, quasi-isolators
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/24—Coupling light guides
    • G02B6/26—Optical coupling means
    • G02B6/35—Optical coupling means having switching means
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
    • G01J9/00—Measuring optical phase difference; Determining degree of coherence; Measuring optical wavelength
    • G01J9/02—Measuring optical phase difference; Determining degree of coherence; Measuring optical wavelength by interferometric methods
    • G01J2009/0226—Fibres

Abstract

The present invention relates to a phase light measuring system comprising: a light source part emitting light; a bandwidth division part generating and outputting a divided light obtained by dividing a bandwidth of light emitted from the light source part into a plurality of bandwidths; and a processing part irradiating a measured object with the divided light output from the bandwidth division part and detecting light reflected from the measured object to be processed. The bandwidth division part has an optical fiber grid applied thereto. The optical fiber grid is connected between the light source part and the processing part, has a grid formed thereon to reflect light corresponding to a first wavelength set within a bandwidth of light output from the light source part and generates a first separated light and a second separated light, which are separated based on the first wavelength, to be output to the processing part. The phase light measuring system provides an advantage that a structure for generating a bandwidth of divided light can be simplified.

Description

≪ Desc / Clms Page number 1 > optical-phase imaging system &

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a phase light measurement system, and more particularly, to a phase light measurement system that uses a plurality of divided light beams generated by dividing a wavelength band of a light source.

The optical phase measurement system that measures and images the phase change of the light incident on the object to be measured can exhibit a resolution exceeding the optical diffraction limit, so that the research and development has been made steadily.

Such phase light measurement methods include a phase contrast method, a phase-shifting method, a digital holography method, a Fourier phase microscopy method, a light interference phase microscope optical coherence phase microscopy).

All of these optical phase measurements have phase wrapping (2π ambiguity) problems.

That is, in a phase measurement method having a geometrical optical structure for measuring light reflected from a probe stage, the phase value ?? of light to be measured has a relationship expressed by Equation 1 below when converted into a sample change amount? Z.

Figure 112015122858994-pat00001

Where λ 0 is the center wavelength of the light source used, and n is the average refractive index between the reference end and the sample end. In this case, since the measured phase value is in the range of 0 to 2 [radian], there is a problem that the maximum measuring range is limited to a half wavelength of the light source used.

To solve this phase wrapping, a software algorithm or a hardware configuration is used. The most commonly used method is a simple phase unwrapping algorithm, which adds or subtracts 2π each time a jump of the measured phase value occurs. This is problematic because the same amount is added and subtracted by 2 n π when the jump occurs.

Other software approaches are not as efficient as complex algorithms and many operations, and the hardware approach complicates setup, including additional optics and measurement stages.

In order to solve these problems, a phase measurement method using multi-wavelengths has been proposed, which can obtain a new long wavelength that can replace the central wavelength λ 0 of the above relation, thereby increasing the maximum measurement range of the sample variation amount Δz .

In this multi-wavelength measurement method, the present applicant has proposed a split light beam obtained by dividing the bandwidth of the light source in the Korean Patent No. 10-1308433.

In other words, we divide the total bandwidth into two, measure the phase for each divided bandwidth, and then obtain a new wavelength from it, thereby increasing the overall measurement range.

Meanwhile, although the Sagnac loop filter is applied to generate the band-split light, the structure is complicated and a more simple structure is required.

It is an object of the present invention to provide a phase light measuring system which can generate a band-split light and can simplify a structure.

According to an aspect of the present invention, there is provided a phase light measuring system comprising: a light source for emitting light; a band dividing unit for generating and outputting divided light obtained by dividing a bandwidth of light emitted from the light source into a plurality of bandwidths; And a processing section for irradiating the measurement object with the divided light output from the band dividing section and detecting and processing the light reflected from the measurement target object, wherein the band dividing section is connected between the light source section and the processing section And a grating for reflecting the light corresponding to the first wavelength set within the bandwidth of the light output from the light source unit is formed to generate first and second divided lights mutually divided centering on the first wavelength and output to the processing unit And a fiber grating.

The first wavelength reflected by the grating of the optical fiber grating is applied with a center wavelength corresponding to the center of the bandwidth of the light emitted from the light source.

According to an aspect of the present invention, the processing unit includes: a first optical coupler that distributes light input through a first input terminal connected to an output terminal of the optical fiber grating through a first distribution terminal and a second distribution terminal; A probe unit which irradiates the light transmitted to the measurement object and transmits the light reflected from the measurement object inversely; A first optical circulator for transmitting the light output through the first distribution stage to the probe unit and outputting the light collected by the probe unit to the first collection path after being reflected from the measurement object; A second optical circulator for irradiating light output through the second distribution stage to a reference mirror and outputting light reflected from the reference mirror to a second collection path; A second optical coupler for multiplexing and outputting light transmitted from the first collecting path and the second collecting path; A photodetector for detecting light output from the second optical coupler; And a measurement unit that acquires information on the measurement target object from the signal output from the optical detection unit.

The light source unit may include a light source for emitting light; And an optical switch which is controlled by the processing section and outputs light emitted from the light source to a first output path leading to the optical fiber grating and a second output path different from the first output path, 2 output path is connected to a second input terminal of the first optical coupler which is separated from the first input terminal and is capable of distributing input light through the first distribution terminal and the second distribution terminal and outputting the divided light, .

The phase light measurement system according to the present invention provides an advantage that the structure for generating the band-split light is simplified.

1 is a view showing a phase light measurement system according to the present invention.

Hereinafter, a phase light measurement system according to a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

1 is a view showing a phase light measurement system according to the present invention.

Referring to FIG. 1, a phase light measuring system 100 according to the present invention includes a light source 110, a fiber grating 130, and a processing unit 150.

The light source unit 110 emits light having a bandwidth.

The light source unit 110 includes a light source 111 and an optical switch 113 that emit light having a bandwidth.

The light source 111 may be a variable wavelength light source for outputting light while varying wavelengths at a predetermined cycle, or a broadband light source for simultaneously emitting light having a wide range of wavelengths.

The optical switch 113 is adapted to selectively use the light emitted from the light source as it is or the method of generating and using the split light according to the measurement conditions.

The optical switch 113 is controlled by the measuring unit 180 and includes a first output path 113a that leads to the optical fiber grating 130 and a second output path 113b that is different from the first output path 113a And the second output path 113b.

That is, when the first output path 113a selection control signal is received by the measuring unit 180, the optical switch 113 transmits the light emitted from the light source 111 to the first output path 113a .

When the second output path 113b selection control signal is received by the measuring unit 180, the optical switch 113 outputs the light emitted from the light source 111 to the second output path 113b.

The second output path 113b is connected to the second input terminal 151b of the first optical coupler 151 through an optical fiber 135. [

The optical fiber grating 130 is applied as a band dividing unit for generating and outputting divided light obtained by dividing the bandwidth of light emitted from the light source unit into a plurality of bandwidths. The optical fiber grating 130 is connected between the light source unit 110 and the processing unit 150, And outputs the first and second divided lights split to each other around the first wavelength to the processing unit 150. The first and second divided lights are divided into the first and second divided lights.

The optical fiber grating 130 is connected between the first output path 113a of the optical switch 113 and the first input terminal 151a of the first optical coupler 151. [

The optical fiber grating 130 reflects the light of the first wavelength determined by the interval between the gratings 131 by the grating 131, and the remaining light is transmitted through the grating 131 .

Here, the first wavelength reflected by the grating 131 of the optical fiber grating 130 is a reference center wavelength? 0 corresponding to the center of the bandwidth of the light emitted from the light source 111 of the light source 110.

In this case, the light having the reference center wavelength λ 0 emitted from the light source 111 passes through the optical fiber grating 130, and passes through the first and second split beams having the first center wavelength λ 1 and the second center wavelength λ 2 , Is generated.

That is, the reference center wavelength of light emitted by the light source (111), λ 0 of light is λ 0 of light is reflected by the grating 131 in the optical fiber grating 130, the procedure proceeds in the reverse, having a wavelength longer by around λ 0 The first split light and the second split light having a short wavelength transmit the grating 131.

The processing unit 150 irradiates the measurement target 10 with the first and second split lights output from the optical fiber grating 130 applied as a band division unit and detects and processes the light reflected from the measurement target 10.

The processing unit 150 includes a first optical coupler 151, a first optical circulator 161, a first optical circulator 162, a probe unit 170, a second optical coupler 174, a photodetector unit 176, And a measurement unit 180.

The first optical coupler 151 distributes the light input through the first input terminal 151a connected to the output terminal of the optical fiber grating 130 through the first distribution terminal 152a and the second distribution terminal 152b, do.

The first optical coupler 151 distributes the light inputted through the second input terminal 151b through the second output path 113b through the first distribution terminal 152a and the second distribution terminal 152b to output do.

The probe unit 170 irradiates the light transmitted from the first optical circulator 161 to the measurement target object 10 and transmits the light reflected from the measurement target object 10 back to the first optical circulator 161 do.

The probe unit 170 includes a plurality of lenses arranged in a housing (not shown) for converting the light emitted from the optical fiber extending from the first optical circulator 161 into parallel light and focusing the light onto the measurement target 10 .

It is needless to say that the probe unit 170 can be constructed so as to be able to switch the traveling direction of the light by user's manipulation.

The first optical circulator 161 transmits the light output through the first distribution stage 152a to the probe unit 170 and transmits the light reflected by the measurement target object 10 and collected by the probe unit 170 1 collection path 163a.

The second optical circulator 162 irradiates the light output through the second distribution stage 152b to the reference mirror 165 and outputs the light reflected from the reference mirror 165 to the second collection path 163b do.

The second optical coupler 174 outputs the interference light generated by combining the light transmitted from the first collecting path 163a and the second collecting path 163b to the optical detecting unit 176. [

The optical detector 176 converts the light output from the second optical coupler into an electrical signal and outputs the electrical signal.

The photodetector 176 may be a spectrometer when a photodiode is applied when the light source 111 is a variable wavelength light source, and when a broadband light source that emits light having a bandwidth is applied.

The measurement unit 180 acquires information about the measurement target 10 from a signal output from the light detection unit 176. [

The measurement unit 180 supports a first mode in which the first and second split lights are used and a normal mode so that the user can select the normal mode through an operation unit (not shown). In the first mode, 1 output path 113a and controls the optical switch 113 to be connected to the second output path 113b in the normal mode.

In the normal mode, the light emitted from the light source 111 is directly transmitted to the probe unit 170 and the mirror 165 to generate an image of the measurement target 10 and display the image on the display unit (not shown).

In the first mode, the first and second divided lights generated through the optical fiber grating 130 are transmitted to the probe unit 170 and the mirror 165 to generate an image for the measurement target 10, Not shown).

On the other hand, when the measurement object 10 is applied to the skin, considering the fact that the proportion of the light that is scattered back from the skin in response to the light incident on the skin is low, the first light The coupler 151 is applied so that 80 to 90% of the input light is distributed to the first distribution stage 151a and the remainder is distributed to the second distribution stage 152b.

The measurement unit 180 measures the phase value of the first center wavelength lambda 1 of the first divided light and the second center wavelength lambda 2 of the second divided light which are known and recorded in advance at the same position of the measurement target body 10 From the photodetector 176, and generates image information of the measurement object 10 through calculation from the acquired phase values.

Meanwhile, the process of obtaining image information of the measurement target object 10 using the first and second split lights of the measurement unit 180 is described in detail in the above-mentioned Japanese Patent Registration No. 10-1308433, do.

In this case, the light emitted from the light source 111 is transmitted through the optical fiber grating 130 to the first optical coupler 151, and the optical switch 113 ) Can be omitted.

According to the phase light measurement system described above, the structure is simplified by applying the optical fiber grating 130 as an element for generating the band-split light.

110: light source 130: fiber grating
150:

Claims (5)

A band dividing section for generating and outputting divided light obtained by dividing a bandwidth of light emitted from the light source section into a plurality of bandwidths; And a processing section for detecting and processing the light reflected from the measurement object,
The band division unit
A grating that is connected between the light source unit and the processing unit and reflects light corresponding to a first wavelength set within a bandwidth of light output from the light source unit is formed and the first and second split light beams, And outputting the generated optical signal to the processing unit. The system of claim 1, wherein the first wavelength reflected by the grating of the optical fiber grating is a center wavelength corresponding to a center of a bandwidth of light emitted from the light source. 3. The apparatus of claim 2, wherein the processing unit
A first optical coupler for distributing light input through a first input terminal connected to an output terminal of the optical fiber grating through a first distribution terminal and a second distribution terminal;
A probe unit which irradiates the light transmitted to the measurement object and transmits the light reflected from the measurement object inversely;
A first optical circulator for transmitting the light output through the first distribution stage to the probe unit and outputting the light collected by the probe unit to the first collection path after being reflected from the measurement object;
A second optical circulator for irradiating light output through the second distribution stage to a reference mirror and outputting light reflected from the reference mirror to a second collection path;
A second optical coupler for multiplexing and outputting light transmitted from the first collecting path and the second collecting path;
A photodetector for detecting light output from the second optical coupler;
And a measuring unit that obtains information on a measurement target object from a signal output from the optical detection unit. The light source unit according to claim 3,
A light source for emitting light;
And an optical switch which is controlled by the processing unit and outputs light emitted from the light source to a first output path leading to the optical fiber grating and a second output path different from the first output path,
And the second output path is connected to a second input terminal of the first optical coupler which is separated from the first input terminal and is capable of distributing input light through the first and second distribution terminals and outputting the input light. Phase optical measurement system. The system of claim 4, wherein the first optocoupler distributes 80% to 90% of the input light to the first distribution stage and the remainder is distributed to the second distribution stage.



KR1020150179241A 2015-12-15 2015-12-15 optical-phase imaging system KR101730445B1 (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR102285059B1 (en) * 2020-04-21 2021-08-04 한국광기술원 apparatus of inspecting barrel of gun

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR102285059B1 (en) * 2020-04-21 2021-08-04 한국광기술원 apparatus of inspecting barrel of gun

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