Terahertz Optoelectronics
Topics in Applied Physics/Volume97 Editor : Kiyomi.Sakai
*Publisher* Springer / National Institute of Information and Communications Technology ISBN : 3-540-20013-4 page 387
Contents
Intoroduction to Terahertz Pulses
Kiyomi Sakai, Masahiko Tani
1		Historical Introduction
2		Principles of Terahertz-Pulse Generation
		2.1				Terahertz-Pulse Emission from Photoconductive Antennas
		2.2				Terahertz-Pulse Emission from Extended Photoconductive Sources
		2.3				Terahertz-Pulse Emission other than Photoconductive Antennas
						2.3.1	Optical Rectification in Nonlinear Media
						2.3.2	Surge Current at the Semiconductor Surface
						2.3.3	Terahertz-Pulse Emission from Semiconductor Quantum Structures
						2.3.4	Terahertz-Pulse Emission from Coherent Longitudinal Optical Phonons
						2.3.5	Terahertz-Pulse Emission from a High-Tc Superconducting Bridge
						2.3.6	All-Electrical Terahertz-Pulse Emission and Detection
3		Principes of Terahertz-Pulse Detection
		3.1				Terahertz-Pulse Detection with Photoconductive Antennas
		3.2				Terahertz-Pulse Detection with Electro-Optic Crystals
		3.3				Terahertz-Pulse Detection with Interferometers
		3.4				Optical Setups for Terahertz-Pulse Emissions and Detection
4		Some Experimental Results
5		Conclusions
References
Generation and Detection of Broadband Pulsed Terahertz Radiation
Shunsuke Kono, Masahiko Tani, Kiyomi Sakai
1		Ultra-Broadband Terahertz Radiations with Nonlinear Crystals
		1.1				Ultra-Broadband Detection of Terahertz Pulses with Electro-Optic Crystals: Principles
						1.1.1	Frequency Response of Electro-Optic Sampling
						1.1.2	Some Experimental Examples on Broadband Electro-Optic Detection
		1.2				Ultra-Broadband Emission Based on Optical Rectification
						1.2.1	Principles of Optical Rectification
						1.2.2	Experimental Results of Broadband Optical Rectification
						1.2.3	Phase-Matched Optical Rectification for Broadband Terahertz Pulses
2		Ultra-Broadband Terahertz Pulses with Photoconductive Antenna
		2.1				Ultra-broadband Detection of Terahertz Pulses with Photoconductive Antennas
						2.1.1	Detection Principles of Photoconductive Antenna
						2.1.2	Experimental Findings of the Broadband Terahertz Detection with a Photoconductive Antenna
						2.1.3	Demonstration of Broadband Photoconductive Detection
						2.1.4	Spectral Response of Photoconductive Antenna in Broadband Detection
						2.1.5	Photoconductive Antenna Response with Different Gating Pulse Widths
						2.1.6	Effects of Antenna Structure
						2.1.7	Signal-to-Noise Characteristics in Broadband Photoconductive Detection
						2.1.8	Experimental Techniques for the Application of Photoconductive Antenna for Broadband Detection
						2.1.9	Discussions .
		2.2				Ultra-Broadband Generation of Terahertz Radiation with Photoconductive Antenna
						2.2.1	Generation of Broadband Terahertz Radiation with Photoconductive Antenna
						2.2.2	Frequency Distribution of Broadband Terahertz Radiation from Photoconductive Antenna
						2.2.3	Comparison of Radiation Bandwidth.
3		Conclusions
References
Terahertz Radiation from Semiconductor Surfaces
Ping Gu, Masahiko Tani
1		Introduction
2		Terahertz Radiation from Semiconductor Surfaces
		2.1				Optical Rectification
		2.2				Surge Current
						2.2.1	Surface Depletion Field
						2.2.2	Photo-Dember Effect
3		Terahertz Radiation from Coherent Phonons and Plasmons
		3.1				Coupling of Transverse Electromagnetic Waves with Longitudinal Coherent Phonons and/or Plasmons
						3.1.1	Coupling to LO Phonons
						3.1.2	Coupling to Plasma Oscillations
						3.1.3	Coherent-Phonon Excitation Mechanisms
		3.2				THz Radiation from Coherent Phonons .
						3.2.1	THz Radiation from Coherent Phonons in Telluride Compound Semiconductors
						3.2.2	Experimental Setup
						3.2.3	Sample Properties
						3.2.4	Spectra of Te, PbTe, and CdTe
						3.2.5	Spectral Dip at TO-Phonon Frequency
						3.2.6	Radiation Pattern and Emission Efficiency
		3.3				Coupling of LO Phonon and Plasmon
						3.3.1	InSb Phonon-Plasmon THz Emission
4		Conclusions
References
Enhanced Generation of Terahertz Radiation from Semiconductor Surfaces with External Magnetic Field
Hideyuki Ohtake, Shingo Ono, Nobuhiko Sarukura
1		Introduction
2		Terahertz Radiation from Semiconductor Surfaces in a Magnetic Field
		2.1				Emission Mechanism of Terahertz Radiation
		2.2				Terahertz-Radiation Power and Polarization Emitted from GaAs, InP, InAs, and InSb
3		Terahertz Radiation from InAs in Magnetic Field
		3.1				Emission of Terahertz Radiation up to 5-T Magnetic Field
		3.2				Emission of Terahertz Radiation up to 14-T Magnetic Field
4		Compact THz-Radiation Source with 2-T Permanent Magnet and Fiber Laser
		4.1				Experimental Setup
		4.2				Notebook-Computer-Size THz Emitter
References
Terahertz Radiation from Bulk and Quantum Semiconductor Structures
Yutaka Kadoya, Kazuhiko Hirakawa
1		Introduction
2		Nonstationary Carrier Transport in Strongly Biased Bulk Semiconductors
		2.1				A Brief Review on Nonstationary Carrier Transport and THz Wave Radiation
		2.2				Time-Domain THz Measurements of Transient Carrier Velocities in Strongly Biased Semiconductors
		2.3				Effect of Sample Geometry on the THz Time-Domain Data
		2.4				Field-Dependent Carrier Velocities in Steady States
3		Bloch Oscillation and THz Gain in Semiconductor Superlattices
		3.1				Bloch Oscillation in Semiconductor Superlattices
		3.2				Superlattice Samples and Time-Domain THz Autocorrelation Spectroscopy
		3.3				Time-Domain Determination of High-Frequency Carrier Conductivities in Superlattices
		3.4				Zener Tunneling into Higher Minibands and High-Frequency Limit of the Bloch Gain
4		THz Radiation From Semiconductor Microcavities in Strong Exciton-Photon Coupling Regime
		4.1				Cavity-Polaritons and the Idea of THz Wave Radiation
		4.2				The Microcavity Samples and the Cavity-Polariton Modes under a Static Electric Field
		4.3				Observation of THz Wave Emissions from Cavity-Polaritons .
		4.4				Transition from Strong- to Weak-Coupling Regime
5		THz Radiation from Bulk Semiconductor Microcavities
		5.1				THz Wave Radiation from Semiconductor Surfaces: A Revisit
		5.2				Enhancement of THz Wave Generation Efficiency
		5.3				Field Screening by Carrier Accumulation
6		Summary
References
Generation of CW Terahertz Radiation with Photomixing
Shuji Matsuura, Hiroshi Ito
1		Introduction
2		Principles of Generation of CW Terahertz Radiation
3		Basic Characteristics of CW Terahertz Radiation with Photomixing
4		Increased Terahertz Radiation Power
		4.1				Optimization of Antenna Design
		4.2				High-Power Laser Sources
		4.3				Thermal Conductivity of Substrate
		4.4				Quantum Efficiency
		4.5				Large Active Area Design
		4.6				Traveling-wave Photomixer
5		Uni-Traveling-Carrier Photodiode ・Novel Photomixer
6		Optical-Terahertz Conversion Efficiency
7		Noise Behavior
8		Spectroscopic Applications
		8.1				Terahertz Spectroscopy in Laboratory
		8.2				Frequency-stabilized Systems for Molecular Spectroscopy
		8.3				Local-Oscillator Application for Heterodyne Detection
9		Summary and Future Trends
Referencesmc
Terahertz Time-domain Spectroscopy
Seizi Nishizawa, Kiyomi Sakai, Masanoi Hangyo, Takeshi Nagashima, Mitsuo Wada Takeda, Keisuke Tominaga, Asako Oka, Koichiro Tanaka, Osamu Morikawa
1		Introduction
2		Principles of THz-TDS
		2.1				Transmission Spectroscopy
		2.2				Reflection Spectroscopy.
3		Application of THz-TDS
		3.1				Semiconductors
		3.2				Ferroelectrics .
						3.2.1	Transmission Spectra of Ferroelectric Crystals .
						3.2.2	Phonon-Polariton Dispersion
		3.3				Photonic Crystals
						3.3.1	Transmission Spectra
						3.3.2	Dispersion Relations of Photonic Bands
		3.4				Biological Molecules
						3.4.1	Small Biological Molecules
						3.4.2	Biological Macromolecules
						3.4.3	Related Studies and Future Perspectives
		3.5				Attenuated Total Reflection Spectroscopy
		3.6				Ellipsometry
		3.7				Generation of Electromagnetic Radiation with Multimode Laser Diode
						3.7.1	Spectrum of the Source MLD, Photomixing Efficiency and Output Spectrum.
						3.7.2	Spectroscopic Applications: Characterization of Si Wafers
						3.7.3	TDS System with MLD-PC.
4		Summary
References
Terahertz Optics in Strongly Correlated Electron Systems
Noriaki Kida, Hironaru Murakami, Masayoshi Tonouchi
1		Introduction
2		Terahertz Radiation from High-Tc Superconductors
		2.1				Terahertz Radiation and Detection System.
		2.2				Terahertz Radiation from YBa2Cu3O7-δ
		2.3				Terahertz Radiation from Highly Anistropic High-Tc Superconductors
						2.3.1	General Properties of Terahertz Radiation from Bi2Sr2CaCu2O8+δ and Tl2Ba2CaCu2O8+δ
						2.3.2	Temperature Dependence of Terahertz Radiation from Bi2Sr2CaCu2O8+δ and Tl2Ba2CaCu2O8+δ
						2.3.3	Fourier Components of Terahertz Pulses
						2.3.4	Coherent Terahertz-wave Radiation from Tl2Ba2CaCu2O8+δ Caused by Josephson Plasma Resonance
3		Terahertz Radiation from Colossal Magnetoresistive Manganites
		3.1				Methods
		3.2				Terahertz Radiation from Magnetoresistive Pr0.7Ca0.3MnO3
						3.2.1	Laser-Power and Bias-Voltage Dependences
						3.2.2	Temperature Dependence.
		3.3				Reversible and Bistable Terahertz Radiation
4		Terahertz Time-domain Spectroscopy of Strongly Correlated Electron Systems
		4.1				Ultrafast Carrier Dynamics in Underdoped Bi2Sr2CaCu2O8+δ
						4.1.1	Coexistence of Superconducting Gap and Pseudogap in Underdoped Bi2Sr2CaCu2O8+δ
						4.1.2	Ultrafast Superconductivity Fluctuation in Underdoped Bi2Sr2CaCu2O8+δ .
		4.2				Low-energy Charge Dynamics in Half-metallic Ferromagnets
						4.2.1	Methods
						4.2.2	100% Spin-polarized Ferromagnetic Metallic Phase
						4.3.3	Temperature Dependence of the Ferromagnetic Metallic Phase
		4.3				Observation of a Collective Excitation Mode in Charge-ordered Manganites
						4.3.1	Observation of the Finite Frequency Peak
						4.3.2	Origin of the Finite Frequency Peak
						4.3.3	Collective ExcitationMode due to Charge-density-wave Condensate
References
Terahertz Imaging
Michael Herrmann, Ryoichi Fukasawa, Osamu Morikawa
1		Variants of THz Imaging Equipment
		1.1				Scanning THz Imaging System Based on Photoconductive Antennas
		1.2				Real-Time THz Imaging Based on Electro-Optic Sampling
2		Basic Properties of THz Images
		2.1				Display Modes
		2.2				Diffraction and Image Resolution
3		THz Imaging Applications to Powders
		3.1				Powders and THz Radiation
		3.2				Imaging Results
		3.3				Identifying Materials
		3.4				Humidity in Powders
		3.5				Powder-Density Relaxation and Local Variations of Powder Density.
		3.6				Powders in Envelopes
4		Characterization of Si Wafers with THz Imaging
		4.1				THz Radiation and Plasmons in Semiconductors
		4.2				Applications to Si Wafers
5		Imaging of Supercurrent Distributions
		5.1				Supercurrent Distribution in a High-Tc Bridge
		5.2				Vector Imaging of a Supercurrent Flow in a High-Tc Thin Film
6		Real-Time THz Imaging
		6.1				Real-Time THz Images
		6.2				Time-Domain THz Imaging
		6.3				THz Spectroscopic Imaging
7		Summary
References
Index