We report a nonlinear terahertz (THz) detection device based on metallic bull's-eye plasmonic antenna. The antenna, fabricated with femtosecond laser direct writing and deposited gallium phosphide (GaP) crystal, focuses incoming THz waveforms within the sub-wavelength bull's eye region to locally enhance field. Additionally, structure minimizes diffraction effects allowing relatively long interaction length between transmitted field co-propagating near-infrared gating pulse used in an...

Abstract Slow motion movies allow us to see intricate details of the mechanical dynamics complex phenomena. If images in each frame are replaced by terahertz (THz) waves, such can monitor low-energy resonances and reveal fast structural or chemical transitions. Here, we combine THz spectroscopy as a non-invasive optical probe with real-time monitoring technique demonstrate ability resolve non-reproducible phenomena at 50k frames per second, extracting generated waveforms every 20 μs. The...

We combine parametric frequency upconversion with the single-photon counting technology to achieve terahertz (THz) detection sensitivity down zeptojoule (zJ) pulse energy level. Our scheme employs a near-infrared ultrafast source, GaP nonlinear crystal, optical filters, and avalanche diode. This configuration is able resolve 1.4 zJ (1.4 × 10 –21 J) THz energy, corresponding 1.5 photons per pulse, when signal averaged within only 1 s (or 50,000 pulses). A single can also be detected its above...

We demonstrate adiabatic rapid passage on a subpicosecond time scale in single semiconductor quantum dot, enabling the exploration of regime strong (and rapidly varying) Rabi energies for optical control excitons. An observed dependence exciton inversion efficiency sign pulse chirp demonstrates dominance phonon-mediated dephasing, which is suppressed positive at low temperature. Our findings will support realization dynamical decoupling strategies and suggest that multiphonon emission and/or...

We present a process flow for wafer-scale fabrication of surface phase grating with sub-micron feature sizes from single semiconductor material. demonstrate this technique using 110-oriented GaP wafer second-order nonlinearity to obtain nanostructured device (800 nm lateral size and 245 height modulation) applications relevant near-infrared optical diffraction time-resolved terahertz (THz) technologies. The involves plasma-enhanced chemical deposition SiO2 layer on the followed by contact...

Femtosecond optical control of the magnetization and coercive field is demonstrated in GaMnAs using time-resolved magneto-optical Kerr effect techniques. These experiments reveal a near-complete, subpicosecond collapse hysteresis loop, consistent with femtosecond demagnetization. On longer time scales (∼300ps) an increase coercivity observed, attributed to hole-mediated enhancement domain wall energy.

In optimal quantum control (OQC), a target state of matter is achieved by tailoring the phase and amplitude Hamiltonian through femtosecond pulse-shaping techniques powerful adaptive feedback algorithms. Motivated recent applications OQC in information science as an approach to optimizing gates atomic molecular systems, here we report experimental implementation solid-state system consisting distinguishable semiconductor dots. We demonstrate simultaneous high-fidelity π 2π single qubit two...

Four-wave mixing experiments on GaMnAs indicate an increase in the optical response near band gap with increasing Mn concentration. These findings are attributed to ($s$,$p$)-$d$ hybridization, which leads enhancement density of states valence band. Our show that nonlinearity four-wave technique provides a highly sensitive probe for Mn-related changes electronic structure GaMnAs.

We have investigated the carrier and magnetization dynamics in a GaMnAs structure with perpendicular uniaxial anisotropy using time-resolved pump probe techniques. Experiments were performed over two orders of magnitude variation fluence, revealing an ultrafast demagnetization response that saturates at fluence values larger than 1 mJ/cm2. Dichroic bleaching contributions exhibit no dependence on circular polarization state beam, indicating signature electron spin dynamics, contrast to...

We demonstrate a table-top high-field terahertz (THz) source based on optical rectification of collimated near-infrared pulse in gallium phosphide (GaP) to produce peak fields above 300 kV/cm with spectrum centered at 2.6 THz. The experimental configuration, tilted-pulse-front phase matching, is implemented grating etched directly onto the front surface GaP crystal. Although THz generation efficiency starts showing saturation onset as energy reaches 0.57 mJ, we can expect our configuration...

We report the observation of a sharp band-edge response in spectrally resolved differential reflectivity experiments on GaMnAs, contrast to linear optical which large band-tail effects are known dominate. The exhibits blue shift relative results GaAs and LT-GaAs, consistent with valence-band model ferromagnetism. Our demonstrate utility nonlinear techniques for studying electronic structure III-Mn-V diluted magnetic semiconductors.

Coherent carrier dynamics are studied in GaMnAs using time-integrated and time-resolved four-wave mixing techniques. Dephasing is observed to be dominated by spin-flip scattering between the optically injected holes Mn ions, revealing rapid time scale of this process III-Mn-V diluted magnetic semiconductors. The optical response shown exhibit characteristic signatures a simple photon echo, despite complexity band tail contributions strong exchange coupling system.

Shaped ultrafast pulses designed for controlled-rotation (C-ROT) operations on exciton qubits in semiconductor quantum dots are demonstrated using a control apparatus operating at ∼1 eV. Optimum pulse shapes employing amplitude and phase shaping protocols implemented the output of an optical parametric oscillator programmable system, characterized autocorrelation multiphoton intrapulse interference scan techniques. We apply our characterization results density matrix simulations to assess...

A detection efficiency measurement system for free-space single-photon detectors has been established at the National Research Council (NRC) Canada. This apparatus incorporates an 850 nm fiber laser source and utilizes a double-attenuation substitution calibration technique. Detection calibrations of silicon avalanche photodiodes (SPADs) incident photon rates in range 1.0×105 counts per second (Cts/s) (36 fW) to 2.1×106Cts/s (734 are SI-traceable through configuration with transfer standard...

Four-wave mixing (FWM) spectroscopy reveals clear signatures associated with the exciton, free carrier inter-band transitions, and Urbach band tail in low-temperature-grown GaAs, providing a direct measure of effective gap as well insight into influence disorder on electronic structure. The ability to detect (and resolve) these contributions, contrast linear spectroscopy, is due an enhanced sensitivity FWM optical joint density states many-body effects. Our experiments demonstrate power for...

The National Research Council (NRC) of Canada has established a next generation facility for the primary realization optical radiant power. main feature this is new cryogenic electrical substitution radiometer with closed-cycle helium cryocooler. A monochromator-based approach allows detector calibrations at any desired wavelength. custom-designed motion apparatus includes two transfer standard mounting ports which increased our measurement capability by allowing calibration photodetectors...

Terahertz time-domain spectroscopy (THz-TDS) is a powerful technique that enables the characterization of large range bulk materials, devices, and products. Although this has been increasingly used in research industry, standard THz-TDS configuration relying on use near-infrared (NIR) laser source remains experimentally complex relatively costly, impeding its availability to those without expertise build high-performance setup based nonlinear optics or financial means acquire commercial...

We demonstrate the selective optical excitation and detection of subsets quantum dots (QDs) within an InAs/InP ensemble using a SiO2/Ta2O5-based microcavity. The low variance exciton transition energy dipole moment tied to narrow linewidth microcavity mode is expected facilitate effective qubit encoding manipulation in dot with ease state readout relative qubits encoded single dots.

The application of femtosecond four-wave mixing to the study fundamental properties diluted magnetic semiconductors ((s,p)-d hybridization, spin-flip scattering) is described, using experiments on GaMnAs as a prototype III-Mn-V system. Spectrally-resolved and time-resolved experimental configurations are including use zero-background autocorrelation techniques for pulse optimization. etching process used prepare samples also highlighted. high temporal resolution this technique, afforded by...

The properties of six large area semiconductor photodetectors were investigated in the near infrared wavelength range. For potential use as transfer standard detectors absolute spectral responsivity calibrations, spatial uniformity and four InGaAs two Ge photodiodes characterized. Spatial measurements carried out at 1000 nm, 1550 1650 nm show that photodiode non-uniformity changes with for both detectors. characterization apparatus, results, analysis are presented.

Dispersive Fourier method gives access to spectral information by mapping them in the time domain. This facilitates shot-to-shot spectroscopy of rapidly changing systems. We adapted this technique demonstrate time-resolved THz at 50 kHz repetition rate encoding waveform onto components spectrally broadened (NIR) ultrafast laser pulses.

Standard terahertz time-domain spectroscopy uses a relatively slow multidata acquisition process that has hindered the technique's ability to resolve ``fast'' dynamics occurring on microsecond timescale. This timescale, inaccessible most ultrafast pump-probe techniques, hosts range of phenomena been left unexplored due lack proper real-time monitoring techniques. In this work, chirped-pulse spectral encoding, photonic time-stretch technique, and high-speed electronics are used demonstrate...

Abstract We have developed a technique to determine the electrical substitution power of cryogenic optical radiant detector, that directly implements frequency-programmable Josephson voltage standard (FPJVS), thus reducing traceability chain. The detector and reference are combined inside common environment. demonstrate practicality by using FPJVS apply known across resistive heater NIST planar radiometric detector. applied is calculated from measurement resistance voltage. dc bias current...

Overcoming technical performance limitations in the detection and characterization of terahertz (THz) radiation will enable ground-breaking scientific advances from study fast non-reproducible phenomena to enabling THz quantum applications that require single-photon sensitivity. Electro-optic sampling techniques intrinsically rely on acquisition multiple data points reconstruct full waveform, which leads long times, prevents single photons. We have developed two distinct highly sensitive for...