Ultrabroadband photoconductive detection: Comparison with free-space electro-optic sampling

Kono, S.; Tani, Masahiko; Sakai, Kiyomi

doi:10.1063/1.1394719

Cited by 107 publications

(67 citation statements)

References 11 publications

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“…The laser pulse generates free charge carriers in the semiconductor substrate, which are accelerated by E THz thus generating a current I between two contacts. Assuming a laser pulse of the form sech 2 (1.76t/t 0 ) where t 0 is the full-width-athalf-maximum, the current measured through contact i in the photoconductive receiver described here, is related to E THz by 15 :…”

mentioning

confidence: 99%

Polarization-sensitive terahertz detection by multicontact photoconductive receivers

Castro-Camus

Lloyd‐Hughes

Johnston

et al. 2005

Applied Physics Letters

127

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We have developed a terahertz radiation detector that measures both the amplitude and polarisation of the electric field as a function of time. The device is a three-contact photoconductive receiver designed so that two orthogonal electric field components of an arbitrary polarised electromagnetic wave may be detected simultaneously. The detector was fabricated on Fe + ion-implanted InP. Polarisation-sensitive detection is demonstrated with an extinction ratio better than 100:1. This type of device will have immediate application in studies of birefringent and optically active materials in the far-infrared region of the spectrum.PACS numbers: 07.57.Kp , 07.57.Pt, 07.60.Fs, 42.25.Ja, 71.55.Eq , 78.20.Ek, 78.20.Fm The far-infrared, or terahertz (THz), region of the electromagnetic spectrum encompasses the energy range of many collective processes in condensed matter physics and macromolecular chemistry. However, in the past this spectral region has been relatively unexplored owing to a lack of bright radiation sources and appropriate detectors. The technique of THz time domain spectroscopy (TDS), 1,2 which has developed rapidly as a result of advances in ultra-short pulsed laser technology, now provides a very sensitive probe across the THz band. TDS is currently an invaluable tool in condensed matter physics 3,4,5 and macromolecular chemistry. 6,7To date THz-TDS techniques have relied on linearly polarised emitters and detectors. However, for spectroscopy of birefringent and optically active materials it is also important to measure the polarisation state of radiation before and after it has interacted with the material. Here we report on a detector that enables such a THz-TDS system to be realised.Vibrational circular dichroism (VCD) spectroscopy is a new technique which has substantial potential in the fields of macromolecular chemistry and structural biology. 8 Akin to the established technique of (ultraviolet) circular dichroism, VCD is used to analyse the structure of chiral molecules. It is predicted that VCD will be more powerful than conventional circular dichroism for stereo-chemical structure determination. 8 However the technique is currently limited by insensitive and narrow band spectrometers.Of particular interest to biochemists is the structure and function of proteins and nucleic acids. These chiral biomolecules have vibrational and librational modes in the THz region and the THz optical activity of these modes are starting to be studied experimentally. 9,10 THz frequency VCD is already finding application in fields as distinct as biochemical research 11 and astrobiology. 10 In the future the ability to perform VCD using a polarisation sensitive THz-TDS technique should enhance the bandwidth and sensitivity of measurements, and allow dynamic time-resolved studies to be performed.In order to perform polarisation sensitive THz-TDS, it is necessary to be able to measure two (preferably orthogonal) electric field components of a terahertz transient. Theoretically it is possible to do this using a ...

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mentioning

confidence: 99%

Polarization-sensitive terahertz detection by multicontact photoconductive receivers

Castro-Camus

Lloyd‐Hughes

Johnston

et al. 2005

Applied Physics Letters

127

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“…First attempts of low-temperature growth of In 0.53 Ga 0. 47 As lattice matched to InP substrates were performed in [98]. It has been found that the layers grown at the lowest temperatures (180 o C) were characterised by rather short carrier lifetimes of~2.3 ps, but had very low resistivity.…”

Section: Ingaasmentioning

confidence: 99%

“…Indeed, LTG GaAs and related materials match most of the requirements for making efficient ultrafast optoelectronic devices such as short carrier lifetime, high electron mobility, high electric breakdown field, and large dark resistivity [42]. Components manufactured from LTG GaAs have been used for subpicosecond electric pulse generation [43], all optical switching [44], laser mode locking [45], and, most importantly, for generation and detection of THz pulses with extremely broad frequency bands [46,47] as well as for narrow-band CW THz generation [48].…”

Section: Radiation-damaged Silicon-on-sapphirementioning

confidence: 99%

“…Doping of LTG In 0.53 Ga 0. 47 As with Be has led to some reduction of the free electron density [99,100] (from approximately 2.4·10 18 cm -3 to 5·10 16 cm -3 (still too large for applications of this material in photoconductor devices); the carrier lifetime has decreased simultaneously to~1.9 ps [101].…”

Section: Ingaasmentioning

confidence: 99%

“…In [29] the system used in Ref. [28] was supplemented with a mechanical shaker for the THz pulse differentiation. This has enhanced the detection efficiency of the photoconductive antenna and has extended its detectable bandwidth to 60 THz.…”

Section: Performance Characteristics Of Thz-tds Systemsmentioning

confidence: 99%

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Semiconductors for terahertz photonics applications

Krotkus¹

2010

J. Phys. D: Appl. Phys.

112

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Abstract:Generation and measurement of ultrashort, sub-picosecond pulses of electromagnetic radiation with their characteristic Fourier spectra that reach far into terahertz (THz) frequency range has recently become a versatile tool of the far-infrared spectroscopy and imaging. This technique -THz time-domain spectroscopy, in addition to a femtosecond pulse laser, requires semiconductor components manufactured from materials with a short photoexcited carrier lifetime, high carrier mobility, and large dark resistivity. Here we will review most important developments in the field of investigation of such materials. Main characteristics of low-temperature-grown or ion-implanted GaAs and semiconducting compounds sensitive in the wavelength ranges around 1 µm and 1.5 µm will be surveyed. The second part of the paper is devoted to the effect of surface emission of THz transients from semiconductors illuminated by femtosecond laser pulses. Main physical mechanisms leading to this emission as well as their manifestation in various crystals will be described.

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Transient Terahertz Spectroscopy for2DMaterials

Xu,

Zhang,

et al. 2023

Two‐Dimensional Materials for Nonlinear Optics

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Ultrabroadband photoconductive detection: Comparison with free-space electro-optic sampling

Cited by 107 publications

References 11 publications

Polarization-sensitive terahertz detection by multicontact photoconductive receivers

Polarization-sensitive terahertz detection by multicontact photoconductive receivers

Semiconductors for terahertz photonics applications

Transient Terahertz Spectroscopy for2DMaterials

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