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Xue K, Wang J, Zhao Y, Xiao Z. Measurement of glass thickness and refractive index based on spectral interference technology. APPLIED OPTICS 2021; 60:7983-7988. [PMID: 34613058 DOI: 10.1364/ao.432918] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Accepted: 08/10/2021] [Indexed: 06/13/2023]
Abstract
A non-contact glass thickness and refractive index measurement method based on spectral interferometry is proposed. The method uses the Michelson interference principle to calculate the interference signal obtained by the spectrometer using the Fourier transform algorithm to obtain the modulation period of the spectral interference fringes. The geometrical thickness and refractive index of a glass sample can be calculated from the optical path difference between the reflected light of the reference arm and that of the front and back surfaces of the glass sample before and after being placed in the measuring arm. The linear interpolation method is used to resample the interference pattern in the frequency domain to ensure uniform sampling. It also adopts an improved phase extraction algorithm in the Fourier domain, which improves the anti-interference ability of the measurement system, and it exhibits a fast detection speed and high signal-to-noise ratio. To verify the accuracy of the measurement results of this method, a high-precision coordinate measuring machine is used for comparative experiments, and the characteristics of the tested object are analyzed. The experimental results show that the measurement accuracy of the system is in good agreement with that of a high-precision coordinate measuring machine.
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Guillen Bonilla JT, Guillen Bonilla H, Rodríguez Betancourtt VM, Sánchez Morales ME, Reyes Gómez J, Casillas Zamora A, Guillen Bonilla A. Low-Finesse Fabry-Pérot Interferometers Applied in the Study of the Relation between the Optical Path Difference and Poles Location. SENSORS 2020; 20:s20020453. [PMID: 31941162 PMCID: PMC7013768 DOI: 10.3390/s20020453] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Revised: 01/01/2020] [Accepted: 01/10/2020] [Indexed: 01/10/2023]
Abstract
Interferometry sensors are frequently analyzed by applying the Fourier transform because the transformation separates all frequency components of its signal, making its study on a complex plane feasible. In this work, we study the relation between the optical path difference (OPD) and poles location theoretically and experimentally, using the Laplace transform and a pole-zero map. Theory and experiments are in concordance. For our study, only the cosine function was considered, which is filtered from the interference pattern. In experimental work, two unperturbed low-finesse Fabry-Pérot interferometers were used. First, a Fabry-Pérot interferometer that has a cavity length of ~1.6 mm was used. Its optical path difference was 2.33 mm and the poles were localized at points ±i12. rad/nm. Secondly, a Fabry-Pérot interferometer with a cavity length of ~5.2 mm was used, and its optical path difference was 7.59 mm and the poles were localized at points ±i40.4 rad/nm. Experimental results confirmed the theoretical analysis. Our proposal finds practical application for interferometer analysis, signal processing of optical fiber sensors, communication system analysis, and multiplexing systems based on interferometers.
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Affiliation(s)
- José Trinidad Guillen Bonilla
- Departamento de Electrónica, Centro Universitario de Ciencias Exactas e Ingenierías (C.U.C.E.I.), Universidad de Guadalajara, Blvd. M. García Barragán 1421, Guadalajara 44410, Mexico;
- Departamento de Matemáticas, Centro Universitario de Ciencias Exactas e Ingenierías (C.U.C.E.I.), Universidad de Guadalajara, Blvd. M. García Barragán 1421, Guadalajara 44410, Mexico
| | - Héctor Guillen Bonilla
- Departamento de Ingeniería de Proyectos, Centro Universitario de Ciencias Exactas e Ingenierías (C.U.C.E.I.), Universidad de Guadalajara, Blvd. M. García Barragán 1421, Guadalajara 44410, Mexico; (H.G.B.); (A.C.Z.)
| | - Verónica María Rodríguez Betancourtt
- Departamento de Química, Centro Universitario de Ciencias Exactas e Ingenierías (C.U.C.E.I.), Universidad de Guadalajara, Blvd. M. García Barragán 1421, Guadalajara 44410, Mexico;
| | - María Eugenia Sánchez Morales
- Departamento de Ciencias Tecnológicas, Centro Universitario de la Ciénega (CUCienéga), Universidad de Guadalajara, Av. Universidad No. 1115, LindaVista, C.P., Ocotlán 47810, Mexico;
| | - Juan Reyes Gómez
- Departamento de Ciencias químicas, Universidad de Colima, Las Víboras, Coquimatlan 28045, Mexico;
| | - Antonio Casillas Zamora
- Departamento de Ingeniería de Proyectos, Centro Universitario de Ciencias Exactas e Ingenierías (C.U.C.E.I.), Universidad de Guadalajara, Blvd. M. García Barragán 1421, Guadalajara 44410, Mexico; (H.G.B.); (A.C.Z.)
| | - Alex Guillen Bonilla
- Departamento de Ciencias Computacionales e Ingenierías, Centro Universitario de los Valles (CUValles), Universidad de Guadalajara, Carretera Guadalajara-Ameca Km. 45.5, Ameca 46600, Mexico
- Correspondence: ; Tel.: +52-(375)-7580-500 (ext. 47417)
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Park HM, Joo KN. High-speed combined NIR low-coherence interferometry for wafer metrology. APPLIED OPTICS 2017; 56:8592-8597. [PMID: 29091673 DOI: 10.1364/ao.56.008592] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2017] [Accepted: 09/26/2017] [Indexed: 06/07/2023]
Abstract
In this investigation, we describe a combined low-coherence interferometric technique to measure the surface and thickness profiles of wafers at once with high speed. The measurement system consists of a spectrally resolved interferometer to provide and monitor the optical path difference between two incident beams of the optical source part and a low-coherence scanning interferometer to measure the dimensions of wafers with significantly shortened scanning length. In the experiments, a silicon wafer and a sapphire wafer, of which both sides are polished, were used as targets of the measurement system for verification of the proposed system. As a result, the scanning length of the low-coherence scanning interferometer was reduced from a few millimeters to a few hundreds of micrometers approximately 10 times. In addition, surface profiles of both sides and thickness profiles were simultaneously measured to reconstruct 3D shapes of wafers.
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Rajai P, Schriemer H, Amjadi A, Munger R. Simultaneous measurement of refractive index and thickness of multilayer systems using Fourier domain optical coherence tomography, part 2: implementation. JOURNAL OF BIOMEDICAL OPTICS 2017; 22:15003. [PMID: 28150009 DOI: 10.1117/1.jbo.22.1.015003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2016] [Accepted: 01/03/2017] [Indexed: 06/06/2023]
Abstract
We introduce a theoretical method for simultaneous measurement of refractive index and thickness of multilayer systems using Fourier domain optical coherence tomography (FD-OCT) without any auxiliary arrangement. The input data to the formalism are the FD-OCT measured optical path lengths (OPLs) and properly selected spectral components of FD-OCT interference spectrum. The outputs of the formalism can be affected significantly by uncertainty in measuring the OPLs. An optimization method is introduced to deal with the relatively large amount of uncertainty in measured OPLs and enhance the final results. Simulation result shows that by using the optimization method, indices can be extracted with the absolute error ? 0.001 for transparent biological samples having indices < 1.55 .
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Affiliation(s)
- Payman Rajai
- University of Ottawa, Physics Department, 150 Louis Pasteur, Ottawa, Ontario K1N 6N5, Canada
| | - Henry Schriemer
- University of Ottawa, Physics Department, 150 Louis Pasteur, Ottawa, Ontario K1N 6N5, CanadabUniversity of Ottawa, School of Electrical Engineering and Computer Science, 25 Templeton Avenue, Ottawa, Ontario K1N 6N5, Canada
| | - Ahmad Amjadi
- Sharif University of Technology, Physics Department, P.O. Box 11155-9161, Tehran, Iran
| | - Rejean Munger
- University of Ottawa, Physics Department, 150 Louis Pasteur, Ottawa, Ontario K1N 6N5, Canada
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Rajai P, Schriemer H, Amjadi A, Munger R. Simultaneous measurement of refractive index and thickness of multilayer systems using Fourier domain optical coherence tomography, part 1: theory. JOURNAL OF BIOMEDICAL OPTICS 2017; 22:15002. [PMID: 28130924 DOI: 10.1117/1.jbo.22.1.015002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2016] [Accepted: 01/03/2017] [Indexed: 06/06/2023]
Abstract
We introduce a theoretical framework for simultaneous refractive index and thickness measurement of multilayer systems using the Fourier domain optical coherence tomography (FD-OCT) system without any previous information about the item under investigation. The input data to the new formalism are the FD-OCT measured optical path lengths and properly selected spectral components of the FD-OCT interference spectrum. No additional arrangement, reference reflector, or mechanical scanning is needed in this approach. Simulation results show that the accuracy of the extracted parameters depends on the index contrast of the sample while it is insensitive to the sample’s thickness profile. For transparent biological samples with smooth interfaces, when the object is in an aqueous medium and has indices < 1.55 , this method can extract indices and thicknesses with the absolute error ? 0.001 .
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Affiliation(s)
- Payman Rajai
- University of Ottawa, Physics Department, 150 Louis Pasteur, Ottawa, Ontario K1N 6N5, Canada
| | - Henry Schriemer
- University of Ottawa, Physics Department, 150 Louis Pasteur, Ottawa, Ontario K1N 6N5, CanadabUniversity of Ottawa, School of Electrical Engineering and Computer Science, Ottawa, Ontario K1N 6N5, Canada
| | - Ahmad Amjadi
- Sharif University of Technology, Physics Department, P.O. Box: 11155-9161, Tehran, Iran
| | - Rejean Munger
- University of Ottawa, Physics Department, 150 Louis Pasteur, Ottawa, Ontario K1N 6N5, Canada
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Park HM, Jung HW, Joo KN. Dual low coherence scanning interferometry for rapid large step height and thickness measurements. OPTICS EXPRESS 2016; 24:28625-28632. [PMID: 27958506 DOI: 10.1364/oe.24.028625] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
In this investigation, we propose a dual low coherence scanning interferometer as the novel concept to measure large height steps on the topographic surface of a specimen and the thickness profile of a transparent optical plate. Dual low coherence characteristics by the tandem interferometric configuration can generate several discrete correlograms for the measured surfaces, which provide the possibility to reduce the scanning length of typical low coherence scanning interferometry significantly. Also, the spectrally-resolved interferometric method is combined to monitor the distance gaps between correlograms caused by the dual low coherence. To verify the proposed interferometry, a large height step specimen and a silicon wafer were used and the 3D surface and thickness profiles were rapidly and successfully measured. In addition, the technique which can identify each correlogram by the insertion of dispersive plates are suggested in this paper.
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Wu H, Zhang F, Liu T, Qu X. Glass thickness and index measurement using optical sampling by cavity tuning. APPLIED OPTICS 2016; 55:9756-9763. [PMID: 27958467 DOI: 10.1364/ao.55.009756] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
In this paper, we describe a method based on optical sampling by cavity tuning, which is capable of high-accuracy glass thickness and index measurement. By tuning the repetition frequency of the frequency comb, a series of cross-correlation patterns can be obtained that correspond to the front and rear surfaces of the specimen and the co-operation mirror. Both the geometrical thickness and the optical thickness of the specimen can be measured via the cross-correlation patterns, and consequently, the glass refractive index can be determined at the same time. The comparison with the reference value shows an agreement within 1.3 μm for the thickness measurement, and within 5×10-4 for the refractive index measurement.
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Research Progress on F-P Interference-Based Fiber-Optic Sensors. SENSORS 2016; 16:s16091424. [PMID: 27598173 PMCID: PMC5038702 DOI: 10.3390/s16091424] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/04/2016] [Revised: 08/24/2016] [Accepted: 08/30/2016] [Indexed: 02/07/2023]
Abstract
We review our works on Fabry-Perot (F-P) interferometric fiber-optic sensors with various applications. We give a general model of F-P interferometric optical fiber sensors including diffraction loss caused by the beam divergence and the Gouy phase shift. Based on different structures of an F-P cavity formed on the end of a single-mode fiber, the F-P interferometric optical sensor has been extended to measurements of the refractive index (RI) of liquids and solids, temperature as well as small displacement. The RI of liquids and solids can be obtained by monitoring the fringe contrast related to Fresnel reflections, while the ambient temperature and small displacement can be obtained by monitoring the wavelength shift of the interference fringes. The F-P interferometric fiber-optic sensors can be used for many scientific and technological applications.
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Zhang K, Tao L, Cheng W, Liu J, Chen Z. Air etalon facilitated simultaneous measurement of group refractive index and thickness using spectral interferometry. APPLIED OPTICS 2014; 53:7483-7486. [PMID: 25402915 DOI: 10.1364/ao.53.007483] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
A simple method based on air etalons of a transparent cavity is proposed to simultaneously measure the group refractive index and thickness of a transparent optical plate by spectral domain low coherence interferometry. In this method, only a single beam path is needed in contrast to the two beam paths, the reference and sample arms, of the conventional Michelson interferometer. An empty cavity is first constructed in the beam path by two glass plates. Then the transparent plate under test is inserted into the cavity, so that two air gaps are formed in the cavity. A beam of light of low coherence length is then transmitted through the cavity in the normal direction. Measurements of the reflected waves by the air gaps before and after the sample plate is put into the cavity allow us to determine the group refractive index (ng) and thickness (d) of the sample simultaneously. The relative precision of the results for d and ng are both approximately 7×10-4.
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Zhang K, Tao L, Cheng W, Liu J, Chen Z. Interference enhancement in spectral domain interferometric measurements on transparent plate. APPLIED OPTICS 2014; 53:5906-5911. [PMID: 25321670 DOI: 10.1364/ao.53.005906] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2014] [Accepted: 08/02/2014] [Indexed: 06/04/2023]
Abstract
In spectral domain interferometry, the interference signal generated by directly reflected waves from the two surfaces of a sample plate under test is greatly enhanced by the blockage of those light waves reflected by the two arm mirrors in the Michelson interferometer. This sample surface-reflected interference signal, being the optical path length of the plate, is therefore identifiable directly from the Fourier-transformed interference spectrum. Consequently, the group refractive index and physical thickness of the plate can be obtained simultaneously without any prior information of them. Moreover, subsequent in situ angular scanning on the interference spectra helps to retrieve the wavelength-dependent phase refractive index and first-order dispersion. The order of magnitude of the relative error for the group refractive index is 10(-4), while that for the phase refractive index and the physical thickness is 10(-3).
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Joo KN. Sub-sampling low coherence scanning interferometry and its application: refractive index measurements of a silicon wafer. APPLIED OPTICS 2013; 52:8644-8649. [PMID: 24513929 DOI: 10.1364/ao.52.008644] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2013] [Accepted: 11/18/2013] [Indexed: 06/03/2023]
Abstract
In this investigation, refractive indices of a silicon (Si) wafer were measured by low-coherence scanning interferometry adopting the sub-sampling technique to reduce measurement time. Based on Fourier domain analysis method, the sub-sampled correlogram was analyzed and the refractive indices were calculated by the simple refractive index model and curve fitting of the phase extracted from the sub-sampled correlogram. In the experiment to verify the proposed technique, near-infrared light emitted by a super-luminescent diode with 1050 nm center wavelength was used as an optical source because it is partially transparent to an undoped Si wafer. As the result of measuring an undoped double-side polished Si wafer, group and phase refractive indices were successfully obtained with the sub-sampled correlogram, and the deviations from the reference value were within 0.001.
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Tsai MT, Chang FY, Lee YJ, Lee JD, Wang HC, Lee CK. Defect detection and property evaluation of indium tin oxide conducting glass using optical coherence tomography. OPTICS EXPRESS 2011; 19:7559-7566. [PMID: 21503064 DOI: 10.1364/oe.19.007559] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
This study demonstrates a new approach for evaluating the properties of indium tin oxide (ITO) conducting glass and identifying defects using optical coherence tomography (OCT). A swept-source OCT system was implemented to scan the ITO conducting glass to enable two-dimensional or three-dimensional imaging. With OCT scanning, the defects can be clearly identified at various depths. Several parameters in addition to morphological information can be estimated simultaneously, including the thickness of the glass substrate, the refractive index, reflection coefficient, and transmission coefficient, all of which can be used to evaluate the quality of ITO conducting glass. This study developed a modified method for evaluating the refractive index of glass substrates without having to perform multiple scans as well as a segmentation algorithm to separate the interfaces. The results show the potential of OCT as an imaging tool for the inspection of defects in ITO conducting glass.
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Affiliation(s)
- Meng-Tsan Tsai
- Department of Electrical Engineering, Chang Gung University, 259, Wen-Hwa 1st Road, Kwei-Shan, Tao-Yuan, 33302 Taiwan.
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Chen JH, Zhao JR, Huang XG, Huang ZJ. Extrinsic fiber-optic Fabry-Perot interferometer sensor for refractive index measurement of optical glass. APPLIED OPTICS 2010; 49:5592-5596. [PMID: 20935706 DOI: 10.1364/ao.49.005592] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
A simple fiber-optic sensor based on Fabry-Perot interference for refractive index measurement of optical glass is investigated both theoretically and experimentally. A broadband light source is coupled into an extrinsic fiber Fabry-Perot cavity formed by the surfaces of a sensing fiber end and the measured sample. The interference signals from the cavity are reflected back into the same fiber. The refractive index of the sample can be obtained by measuring the contrast of the interference fringes. The experimental data meet with the theoretical values very well. The proposed technique is a new method for glass refractive index measurement with a simple, solid, and compact structure.
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Affiliation(s)
- Ji-Huan Chen
- Key Laboratory of Photonic Information Technology of Guangdong Higher Educaiton Institutes, South China Normal University, Guangzhou, 510006, China
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Jin J, Kim JW, Kang CS, Kim JA, Eom TB. Thickness and refractive index measurement of a silicon wafer based on an optical comb. OPTICS EXPRESS 2010; 18:18339-18346. [PMID: 20721226 DOI: 10.1364/oe.18.018339] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
We have proposed and demonstrated a novel method that can determine both the geometrical thickness and refractive index of a silicon wafer at the same time using an optical comb. The geometrical thickness and refractive index of a silicon wafer was determined from the optical thickness using phase information obtained in the spectral domain. In a feasibility test, the geometrical thickness and refractive index of a wafer were measured to be 334.85 microm and 3.50, respectively. The measurement uncertainty for the geometrical thickness was evaluated as 0.95 microm (k = 1) using a preliminary setup.
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Affiliation(s)
- Jonghan Jin
- Center for Length and Time, Division of Physical Metrology, Korea Research Institute of Standards and Science (KRISS), Science Town, Daejeon, 305-340, Republic of Korea.
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Cheng HC, Liu YC. Simultaneous measurement of group refractive index and thickness of optical samples using optical coherence tomography. APPLIED OPTICS 2010; 49:790-797. [PMID: 20154745 DOI: 10.1364/ao.49.000790] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Optical coherence tomography (OCT), based on a Michelson interferometer and utilizing low coherence light as the optical source, is a novel technique for the noninvasive imaging of optical scattering media. A simple OCT scheme based on a 3 x 3 fiber coupler is presented for the simultaneous measurement of the refractive index and thickness of optical samples. The proposed system enables the refractive index and thickness to be determined without any prior knowledge of the sample parameters and is characterized by a simple and compact configuration, a straightforward measurement procedure, and a low cost. The feasibility of the proposed approach is demonstrated experimentally using BK7 and B270 optical glass samples.
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Affiliation(s)
- Hsu-Chih Cheng
- Department of Electro-Optics Engineering, National Formosa University, Yunlin, Taiwan.
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Liu CH, Yeh SC, Huang HL. Thickness measurement system for transparent plates using dual digital versatile disc (DVD) pickups. APPLIED OPTICS 2010; 49:637-643. [PMID: 20119011 DOI: 10.1364/ao.49.000637] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
A low-cost high-precision thickness measurement system for transparent plates that uses dual digital versatile disc (DVD) pickups is proposed. The two DVD pickups are used as the transmitter and the receiver in the measurement system, respectively. One of the DVD pickups emits a laser to the other DVD pickup (receiver) and projects on the photodiode integrated circuit of the receiver. The transparent plate is placed in the optical path to change the focused point that will affect the focusing error signal (FES) of the receiver. Using the FES, a mathematical model for thickness measurement based on the geometric optical method is developed. The experimental results show that the accuracy is 1.5 microm, and the uncertainty is estimated to be +/-1.37 microm for the measured thickness of 150 microm.
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Affiliation(s)
- Chien-Hung Liu
- Institute of Electro-Optical and Materials Science, National Formosa University, Huwei, Yunlin, Taiwan.
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Joo KN, Kim SW. Refractive index measurement by spectrally resolved interferometry using a femtosecond pulse laser. OPTICS LETTERS 2007; 32:647-9. [PMID: 17308589 DOI: 10.1364/ol.32.000647] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
We describe a measurement method of refractive indices by way of spectrally resolved interferometry using a femtosecond pulse laser. The method is dispersion insensitive and requires no prior precise knowledge of the geometrical thickness of the specimen. Not only the group but also the phase refractive index can be determined over the wide spectral range covered by the optical comb of the femtosecond pulse laser in use.
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Affiliation(s)
- Ki-Nam Joo
- Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology, Daejeon, South Korea
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Hirai A, Matsumoto H. Measurement of group refractive index wavelength dependence using a low-coherence tandem interferometer. APPLIED OPTICS 2006; 45:5614-20. [PMID: 16855658 DOI: 10.1364/ao.45.005614] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
A technique for the measurement of the group refractive index wavelength dependence of optical materials using a low-coherence tandem interferometer and a spectrometer is proposed. Four channeled spectra resulting from interferences of light beams from different pairs of optical paths are used for the calculation of optical path differences. The group refractive index wavelength dependence is calculated from these optical path differences generated from the sample under measurement. No a priori information of the geometric thickness of a sample is required. The wavelength dependence of the group refractive index of the samples BK7 parallel plate of 5.200 and 10.025 mm from 675 to 850 nm is experimentally measured with an accuracy of the order of 10(-5) and a repeatability of the order of 10(-9).
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Affiliation(s)
- Akiko Hirai
- National Institute of Advanced Industrial Science and Technology, Central 3, 1-1-1 Umezono, Tsukuba, Ibaraki 305-8563, Japan.
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Wang YP, Chen JP, Li XW, Zhang XH, Hong JX, Ye AL. Simultaneous measurement of various optical parameters in a multilayer optical waveguide by a Michelson precision reflectometer. OPTICS LETTERS 2005; 30:979-81. [PMID: 15906976 DOI: 10.1364/ol.30.000979] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
A novel reflectometer based on Michelson interference is proposed and used to measure various optical parameters of homogeneous multilayer optical waveguides. Refractive indices, thickness, insertion loss, absorbed loss, Fresnel reflectance, and diffuse reflection coefficients of optical waveguides can be measured simultaneously.
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Affiliation(s)
- Yi-Ping Wang
- State Key Laboratory on Fiber-Optic Local Area Network and Advanced Optical Communication Systems, Shanghai Jiao Tong University, Shanghai 200030, China
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