Frequency modulation based continuous-wave terahertz homodyne system.

In this study, inspired by the frequency-modulated continuous-wave (FMCW) method, an operation scheme of continuous-wave (CW) terahertz (THz) homodyne system is proposed and evaluated. For this purpose, we utilized the fast and stable wavelength tuning characteristics of a dual-mode laser (DML) as a beating source. Using the frequency-modulated THz waves generated by DML, a cost-effective and robust operation of CW THz system to be applicable to the measurements of thickness or refractive index of a sample is demonstrated. We believe that the proposed scheme shows a potential to the implementations of compact and fast CW THz measurement systems that can be useful in many THz applications.

[1]  Kyung Hyun Park,et al.  Simple and cost-effective thickness measurement terahertz system based on a compact 1.55 μm λ/4 phase-shifted dual-mode laser. , 2012, Optics express.

[2]  Ole Peters,et al.  Single Sampling Point Detection of Frequency Modulated Terahertz Waves , 2012 .

[3]  Kyung Hyun Park,et al.  Widely Tunable 1.55‐μm Detuned Dual‐Mode Laser Diode for Compact Continuous‐Wave THz Emitter , 2011 .

[4]  D. Yee,et al.  Monolithic dual-mode distributed feedback semiconductor laser for tunable continuous-wave terahertz generation. , 2009, Optics express.

[5]  T. Nagatsuma,et al.  Present and Future of Terahertz Communications , 2011, IEEE Transactions on Terahertz Science and Technology.

[6]  Sascha Preu,et al.  Tunable, continuous-wave Terahertz photomixer sources and applications , 2011 .

[7]  Amnon Yariv,et al.  Multiple source frequency-modulated continuous-wave optical reflectometry: theory and experiment. , 2010, Applied optics.

[8]  Yun-Sik Jin,et al.  Terahertz Dielectric Properties of Polymers , 2006 .

[9]  Kyung Hyun Park,et al.  Continuous-wave terahertz system based on a dual-mode laser for real-time non-contact measurement of thickness and conductivity. , 2014, Optics express.

[10]  Holger Schmitz,et al.  Coherent broadband continuous-wave terahertz spectroscopy on solid-state samples , 2010 .

[11]  N. Spinelli,et al.  Fast Fourier Transform and autocorrelation function for the analysis of complex mass spectra , 2013 .

[12]  Didier Lippens,et al.  THz media characterization by means of coherent homodyne detection, results and potential applications , 2007 .

[13]  T. Nagatsuma,et al.  Phase-Sensitive Terahertz Self-Heterodyne System Based on Photodiode and Low-Temperature-Grown GaAs Photoconductor at 1.55 $\mu{\rm m}$ , 2013, IEEE Sensors Journal.

[14]  H. Ko,et al.  Monolithically integrated optical beat sources toward a single-chip broadband terahertz emitter , 2013 .

[15]  Kyung Hyun Park,et al.  InGaAs Schottky barrier diode array detector for a real-time compact terahertz line scanner. , 2013, Optics express.

[16]  K. Kawase,et al.  Non-destructive terahertz imaging of illicit drugs using spectral fingerprints. , 2003, Optics express.

[17]  Masayoshi Tonouchi,et al.  Cutting-edge terahertz technology , 2007 .

[18]  W. DiNatale,et al.  Generation and detection of coherent terahertz waves using two photomixers , 1998 .

[19]  M. Koch,et al.  Multifrequency continuous wave terahertz spectroscopy for absolute thickness determination , 2010 .

[20]  M. Koch,et al.  Terahertz spectroscopy and imaging – Modern techniques and applications , 2011 .

[21]  C. L. Dennis,et al.  Photomixing up to 3.8 THz in low‐temperature‐grown GaAs , 1995 .

[22]  Z. Barber,et al.  Accuracy of active chirp linearization for broadband frequency modulated continuous wave ladar. , 2010, Applied optics.

[23]  Chan-Shan Yang,et al.  THz conductivities of indium-tin-oxide nanowhiskers as a graded-refractive-index structure. , 2012, Optics express.

[24]  P. Yu,et al.  Frequency-Dependent Complex Conductivities and Dielectric Responses of Indium Tin Oxide Thin Films From the Visible to the Far-Infrared , 2010, IEEE Journal of Quantum Electronics.

[25]  D. Mittleman,et al.  Noncontact semiconductor wafer characterization with the terahertz Hall effect , 1997 .

[26]  Tadao Nagatsuma,et al.  Self-Heterodyne Spectrometer Using Uni-Traveling-Carrier Photodiodes for Terahertz-Wave Generators and Optoelectronic Mixers , 2014, Journal of Lightwave Technology.